org.hsqldb.jdbc
Class jdbcConnection

java.lang.Object
  extended byorg.hsqldb.jdbc.jdbcConnection
All Implemented Interfaces:
Connection

public class jdbcConnection
extends Object
implements Connection

A connection (session) with a specific database. Within the context of a Connection, SQL statements are executed and results are returned.

A Connection's database is able to provide information describing its tables, its supported SQL grammar, its stored procedures, the capabilities of this connection, and so on. This information is obtained with the getMetaData method.

Note: By default the Connection automatically commits changes after executing each statement. If auto commit has been disabled, an explicit commit must be done or database changes will not be saved.


HSQLDB-Specific Information:

To get a Connection to an HSQLDB database, the following code may be used (updated to reflect the most recent recommendations):

Class c = Class.forName ( "org.hsqldb.jdbcDriver" );
Driver d = (Driver) c.newInstance();
DriverManager.registerDriver(d);
Connection c = DriverManager.getConnection (url,user,password);

Under HSQLDB, the database connection <url> must start with 'jdbc:hsqldb:'

Starting with 1.7.2, HSQLDB connection properties (<key-value-pairs>) may be appended to the database connection <url>, using the form:

'<url>[;key=value]*'

Starting with 1.7.2, the allowable forms of the HSQLDB database connection <url> have been extended. However, all legacy forms continue to work, with unchanged semantics. The extensions are as described in the following material:

Network Server Database Connections:

The 1.7.2 Server database connection <url> has changed to take one of the two following forms:

  1. 'jdbc:hsqldb:hsql://host[:port][/<alias>][<key-value-pairs>]'
  2. 'jdbc:hsqldb:hsqls://host[:port][/<alias>][<key-value-pairs>]' (with TLS).

The 1.7.2 WebServer database connection <url> also changes to take one of two following forms:

  1. 'jdbc:hsqldb:http://host[:port][/<alias>][<key-value-pairs>]'
  2. 'jdbc:hsqldb:https://host[:port][/<alias>][<key-value-pairs>]' (with TLS).

In both network server database connection <url> forms, the optional <alias> component is used to identify one of possibly several database instances available at the indicated host and port. If the <alias> component is omitted, then a connection is made to the network server's default database instance (instance 0).

For more information on server configuration regarding mounting multiple databases and assigning them <alias> values, please read the Java API documentation for Server and related chapters in the general documentation, especially the Advanced Users Guide.

Transient, In-Process Database Connections:

The 1.7.2 100% in-memory (transient, in-process) database connection <url> takes one of the two following forms:

  1. 'jdbc:hsqldb:.[<key-value-pairs>]' (the legacy form, extended)
  2. 'jdbc:hsqldb:mem:<alias>[<key-value-pairs>]' (the new form)

With the 1.7.2 transient, in-process database connection <url>, the <alias> component is the key used to look up a transient, in-process database instance amongst the collection of all such instances already in existence within the current class loading context in the current JVM. If no such instance exists, one may be automatically created and mapped to the <alias>, as governed by the 'ifexists=true|false' connection property.

Persistent, In-Process Database Connections:

The 1.7.2 standalone (persistent, in-process) database connection <url> takes one of the three following forms:

  1. 'jdbc:hsqldb:<path>[<key-value-pairs>]' (the legacy form, extended)
  2. 'jdbc:hsqldb:file:<path>[<key-value-pairs>]' (same semantics as the legacy form)
  3. 'jdbc:hsqldb:res:<path>[<key-value-pairs>]' (new form with 'files_in_jar' semantics)
For the persistent, in-process database connection <url>, the <path> component is the path prefix common to all of the files that compose the database.

As of 1.7.2, although other files may be involved (such as transient working files and/or TEXT table CSV data source files), the essential set that may, at any particular point in time, compose an HSQLDB database are:

For example: 'jdbc:hsqldb:file:test' connects to a database composed of some subset of the files listed above, where the expansion of <path> is 'test' prefixed with the path of the working directory fixed at the time the JVM is started.

Under Windows TM , 'jdbc:hsqldb:file:c:\databases\test' connects a database located on drive 'C:' in the directory 'databases', composed of some subset of the files:

 C:\
 +--databases\
    +--test.properties
    +--test.script
    +--test.log
    +--test.data
    +--test.backup
    +--test.lck
 
Under most variations of UNIX, 'jdbc:hsqldb:file:/databases/test' connects to a database located in the directory 'databases' directly under root, once again composed of some subset of the files:

 \
 +--databases\
    +--test.properties
    +--test.script
    +--test.log
    +--test.data
    +--test.backup
    +--test.lck
 
Some Guidelines:

  1. Both relative and absolute database file paths are supported.
  2. Relative database file paths can be specified in a platform independent manner as: '[dir1/dir2/.../dirn/]<file-name-prefix>'.
  3. Specification of absolute file paths is operating-system specific.
    Please read your OS file system documentation.
  4. Specification of network mounts may be operating-system specific.
    Please read your OS file system documentation.
  5. Special care may be needed w.r.t. file path specifications containing whitespace and/or mixed-case.
    Please read your OS file system documentation.

Note: Versions of HSQLDB previous to 1.7.0 did not support creating directories along the file path specified in the persistent, in-process mode database connection <url> form, in the case that they did not already exist. Starting with HSQLDB 1.7.0, directories will be created if they do not already exist., but only if HSQLDB is built under a version of the compiler greater than JDK 1.1.x.

The new 'jdbc:hsqldb:res:<path>' database connection <url> has different semantics than the 'jdbc:hsqldb:file:<path>' form. The semantics are similar to those of a 'files_read_only' database, but with some additional points to consider.

Specifically, the '<path> component of a res: type database connection <url> is used to obtain resource URL objects and therby read the database files as resources on the class path. Moreover, the URL objects must point only to resources contained in one or more jars on the class path (must be jar protocol).

In short, a res: type database connection <url> is designed specifically to connect to a 'files_in_jar' mode database instance, which in turn is designed specifically to operate under a Java WebStartTM configuration, where co-locating the database files in the jars that make up the WebStart application avoids the need for special security configuration or code signing.

Note: Since it is difficult or impossible to determine or control from where classes are being loaded or which class loader is doing the loading under 'files_in_jar' semantics, the <path> component of the database connection <url> is always taken to be relative to the default package. That is, if the <path> component does not start with '/', then '/' is prepended when obtaining the resource URLs used to read the database files.

--

For more information about HSQLDB file structure, various database modes and other attributes such as those controlled through the HSQLDB properties files, please read the general documentation, especially the Advanced Users Guide.


JRE 1.1.x Notes:

In general, JDBC 2 support requires Java 1.2 and above, and JDBC3 requires Java 1.4 and above. In HSQLDB, support for methods introduced in different versions of JDBC depends on the JDK version used for compiling and building HSQLDB.

Since 1.7.0, it is possible to build the product so that all JDBC 2 methods can be called while executing under the version 1.1.x Java Runtime EnvironmentTM. However, in addition to this technique requiring explicit casts to the org.hsqldb.jdbcXXX classes, some of the method calls also require int values that are defined only in the JDBC 2 or greater version of ResultSet interface. For this reason, when the product is compiled under JDK 1.1.x, these values are defined in jdbcResultSet.

In a JRE 1.1.x environment, calling JDBC 2 methods that take or return the JDBC2-only ResultSet values can be achieved by referring to them in parameter specifications and return value comparisons, respectively, as follows:

jdbcResultSet.FETCH_FORWARD
jdbcResultSet.TYPE_FORWARD_ONLY
jdbcResultSet.TYPE_SCROLL_INSENSITIVE
jdbcResultSet.CONCUR_READ_ONLY
// etc.

However, please note that code written to use HSQLDB JDBC 2 features under JDK 1.1.x will not be compatible for use with other JDBC 2 drivers. Please also note that this feature is offered solely as a convenience to developers who must work under JDK 1.1.x due to operating constraints, yet wish to use some of the more advanced features available under the JDBC 2 specification.


(fredt@users)
(boucherb@users)

Version:
1.7.2
Author:
boucherb@users, fredt@users
See Also:
jdbcDriver, jdbcStatement, jdbcPreparedStatement, jdbcCallableStatement, jdbcResultSet, jdbcDatabaseMetaData

Field Summary
protected  boolean isNetConn
          Is this connection to a network server instance.
 
Fields inherited from interface java.sql.Connection
TRANSACTION_NONE, TRANSACTION_READ_COMMITTED, TRANSACTION_READ_UNCOMMITTED, TRANSACTION_REPEATABLE_READ, TRANSACTION_SERIALIZABLE
 
Constructor Summary
jdbcConnection(HsqlProperties props)
          Constructs a new external Connection to an HSQLDB Database.
jdbcConnection(Session c)
          Constructs an INTERNAL Connection, using the specified Session.
 
Method Summary
 void clearWarnings()
           Clears all warnings reported for this Connection object.
 void close()
           Releases this Connection object's database and JDBC resources immediately instead of waiting for them to be automatically released.
 void commit()
           Makes all changes made since the previous commit/rollback permanent and releases any database locks currently held by the Connection.
 Statement createStatement()
           Creates a Statement object for sending SQL statements to the database.
 Statement createStatement(int type, int concurrency)
           Creates a Statement object that will generate ResultSet objects with the given type and concurrency.
 Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability)
           Creates a Statement object that will generate ResultSet objects with the given type, concurrency, and holdability.
 void finalize()
          The default implementation simply attempts to silently close() this Connection
 boolean getAutoCommit()
          Gets the current auto-commit state.
 String getCatalog()
           Returns the Connection's current catalog name.
 int getHoldability()
           Retrieves the current holdability of ResultSet objects created using this Connection object.
 DatabaseMetaData getMetaData()
           Gets the metadata regarding this connection's database.
 int getTransactionIsolation()
           Retrieves this Connection object's current transaction isolation level.
 Map getTypeMap()
           Gets the type map object associated with this connection.
 SQLWarning getWarnings()
           Retrieves the first warning reported by calls on this Connection object.
 boolean isClosed()
          Tests to see if a Connection is closed.
 boolean isReadOnly()
          Tests to see if the connection is in read-only mode.
 String nativeSQL(String sql)
           Converts the given SQL statement into the system's native SQL grammar.
 CallableStatement prepareCall(String sql)
           Creates a CallableStatement object for calling database stored procedures.
 CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency)
           Creates a CallableStatement object that will generate ResultSet objects with the given type and concurrency.
 CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability)
           Creates a CallableStatement object that will generate ResultSet objects with the given type and concurrency.
 PreparedStatement prepareStatement(String sql)
           Creates a PreparedStatement object for sending parameterized SQL statements to the database.
 PreparedStatement prepareStatement(String sql, int autoGeneratedKeys)
           Creates a default PreparedStatement object that has the capability to retrieve auto-generated keys.
 PreparedStatement prepareStatement(String sql, int[] columnIndexes)
           Creates a default PreparedStatement object capable of returning the auto-generated keys designated by the given array.
 PreparedStatement prepareStatement(String sql, int type, int concurrency)
           Creates a PreparedStatement object that will generate ResultSet objects with the given type and concurrency.
 PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability)
           Creates a PreparedStatement object that will generate ResultSet objects with the given type, concurrency, and holdability.
 PreparedStatement prepareStatement(String sql, String[] columnNames)
           Creates a default PreparedStatement object capable of returning the auto-generated keys designated by the given array.
 void releaseSavepoint(Savepoint savepoint)
           Removes the given Savepoint object from the current transaction.
 void rollback()
           Drops all changes made since the previous commit/rollback and releases any database locks currently held by this Connection.
 void rollback(Savepoint savepoint)
           Undoes all changes made after the given Savepoint object was set.
 void setAutoCommit(boolean autoCommit)
           Sets this connection's auto-commit mode to the given state.
 void setCatalog(String catalog)
           Sets a catalog name in order to select a subspace of this Connection's database in which to work.
 void setHoldability(int holdability)
           Changes the holdability of ResultSet objects created using this Connection object to the given holdability.
 void setReadOnly(boolean readonly)
           Puts this connection in read-only mode as a hint to enable database optimizations.
 Savepoint setSavepoint()
           Creates an unnamed savepoint in the current transaction and returns the new Savepoint object that represents it.
 Savepoint setSavepoint(String name)
           Creates a savepoint with the given name in the current transaction and returns the new Savepoint object that represents it.
 void setTransactionIsolation(int level)
           Attempts to change the transaction isolation level for this Connection object to the one given.
 void setTypeMap(Map map)
           Installs the given TypeMap object as the type map for this Connection object.
 
Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

isNetConn

protected boolean isNetConn
Is this connection to a network server instance.

Constructor Detail

jdbcConnection

public jdbcConnection(HsqlProperties props)
               throws SQLException
Constructs a new external Connection to an HSQLDB Database.

This constructor is called on behalf of the java.sql.DriverManager when getting a Connection for use in normal (external) client code.

Internal client code, that being code located in HSQLDB SQL functions and stored procedures, receives an INTERNAL connection constructed by the jdbcConnection(Session) constructor.

Parameters:
props - A Properties object containing the connection properties
Throws:
SQLException - when the user/password combination is invalid, the connection url is invalid, or the Database is unavailable.

The Database may be unavailable for a number of reasons, including network problems or the fact that it may already be in use by another process.


jdbcConnection

public jdbcConnection(Session c)
               throws HsqlException
Constructs an INTERNAL Connection, using the specified Session.

This constructor is called only on behalf of an existing Session (the internal parallel of a Connection), to be used as a parameter to a SQL function or stored procedure that needs to execute in the context of that Session.

When a Java SQL function or stored procedure is called and its first parameter is of type Connection, HSQLDB automatically notices this and constructs an INTERNAL Connection using the current Session. HSQLDB then passes this Connection in the first parameter position, moving any other parameter values specified in the SQL statement to the right by one position.

To read more about this, see Function#getValue().

Notes:

Starting with HSQLDB 1.7.2, INTERNAL connections are not closed by a call to close() or by a SQL DISCONNECT. For HSQLDB developers not involved with writing database internals, this change only applies to connections obtained automatically from the database as the first parameter to stored procedures and SQL functions. This is mainly an issue to developers writing custom SQL function and stored procedure libraries for HSQLDB. Presently, it is recommended that SQL function and stored procedure code avoid depending on closing or issuing a DISCONNECT on a connection obtained in this manner.

Parameters:
c - the Session requesting the construction of this Connection
Throws:
HsqlException - never (reserved for future use);
See Also:
Function
Method Detail

createStatement

public Statement createStatement()
                          throws SQLException
Creates a Statement object for sending SQL statements to the database. SQL statements without parameters are normally executed using Statement objects. If the same SQL statement is executed many times, it may be more efficient to use a PreparedStatement object.

Result sets created using the returned Statement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, support for precompilation at the engine level has been implemented, so it is now much more efficient and performant to use a PreparedStatement object if the same SQL statement is executed many times.

Up to 1.6.1, HSQLDB supported TYPE_FORWARD_ONLY - CONCUR_READ_ONLY results only, so ResultSet objects created using the returned Statement object would always be type TYPE_FORWARD_ONLY with CONCUR_READ_ONLY concurrency.

Starting with 1.7.0, HSQLDB also supports TYPE_SCROLL_INSENSITIVE results.

Notes:

Up to 1.6.1, calling this method returned null if the connection was already closed. This was possibly counter-intuitive to the expectation that an exception would be thrown for closed connections. Starting with 1.7.0. the behaviour is to throw a SQLException if the connection is closed.

Specified by:
createStatement in interface Connection
Returns:
a new default Statement object
Throws:
SQLException - if a database access error occurs

See Also:
createStatement(int,int), createStatement(int,int,int)

prepareStatement

public PreparedStatement prepareStatement(String sql)
                                   throws SQLException
Creates a PreparedStatement object for sending parameterized SQL statements to the database.

A SQL statement with or without IN parameters can be pre-compiled and stored in a PreparedStatement object. This object can then be used to efficiently execute this statement multiple times.

Note: This method is optimized for handling parametric SQL statements that benefit from precompilation. If the driver supports precompilation, the method prepareStatement will send the statement to the database for precompilation. Some drivers may not support precompilation. In this case, the statement may not be sent to the database until the PreparedStatement object is executed. This has no direct effect on users; however, it does affect which methods throw certain SQLException objects.

Result sets created using the returned PreparedStatement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, support for precompilation at the engine level has been implemented, so it is now much more efficient and performant to use a PreparedStatement object if the same SQL statement is executed many times.

Starting with 1.7.2, the support for and behaviour of PreparedStatment has changed. Please read the introductory section of the documentation for org.hsqldb.jdbcPreparedStatement.

Specified by:
prepareStatement in interface Connection
Parameters:
sql - an SQL statement that may contain one or more '?' IN parameter placeholders
Returns:
a new default PreparedStatement object containing the pre-compiled SQL statement
Throws:
SQLException - if a database access error occurs

See Also:
prepareStatement(String,int,int)

prepareCall

public CallableStatement prepareCall(String sql)
                              throws SQLException
Creates a CallableStatement object for calling database stored procedures. The CallableStatement object provides methods for setting up its IN and OUT parameters, and methods for executing the call to a stored procedure.

Note: This method is optimized for handling stored procedure call statements. Some drivers may send the call statement to the database when the method prepareCall is done; others may wait until the CallableStatement object is executed. This has no direct effect on users; however, it does affect which method throws certain SQLExceptions.

Result sets created using the returned CallableStatement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY.

HSQLDB-Specific Information:

Starting with 1.7.2, the support for and behaviour of CallableStatement has changed. Please read the introductory section of the documentation for org.hsqldb.jdbcCallableStatement.

Specified by:
prepareCall in interface Connection
Parameters:
sql - a String object that is the SQL statement to be sent to the database; may contain one or more ? parameters.

Note: Typically the SQL statement is a JDBC function call escape string.

Returns:
a new default CallableStatement object containing the pre-compiled SQL statement
Throws:
SQLException - if a database access error occurs

See Also:
prepareCall(String,int,int)

nativeSQL

public String nativeSQL(String sql)
                 throws SQLException
Converts the given SQL statement into the system's native SQL grammar. A driver may convert the JDBC SQL grammar into its system's native SQL grammar prior to sending it. This method returns the native form of the statement that the driver would have sent.

HSQLDB-Specific Information:

Up to and including 1.7.2, HSQLDB converts the JDBC SQL grammar into the system's native SQL grammar prior to sending it, if escape processing is set true; this method returns the native form of the statement that the driver would send in place of client-specified JDBC SQL grammar.

Before 1.7.2, escape processing was incomplete and also broken in terms of support for nested escapes.

Starting with 1.7.2, escape processing is complete and handles nesting to arbitrary depth, but enforces a very strict interpretation of the syntax and does not detect or process SQL comments.

In essence, the HSQLDB engine directly handles the prescribed syntax and date / time formats specified internal to the JDBC escapes. It also directly offers the XOpen / ODBC extended scalar functions specified available internal to the {fn ...} JDBC escape. As such, the driver simply removes the curly braces and JDBC escape codes in the simplest and fastest fashion possible, by replacing them with whitespace. But to avoid a great deal of complexity, certain forms of input whitespace are currently not recognised. For instance, the driver handles "{?= call ...}" but not "{ ?= call ...} or "{? = call ...}"

Also, comments embedded in SQL are currently not detected or processed and thus may have unexpected effects on the output of this method, for instance causing otherwise valid SQL to become invalid. It is especially important to be aware of this because escape processing is set true by default for Statement objects and is always set true when producing a PreparedStatement from prepareStatement() or CallableStatement from prepareCall(). Currently, it is simply recommended to avoid submitting SQL having comments containing JDBC escape sequence patterns and/or single or double quotation marks, as this will avoid any potential problems. It is intended to implement a less strict handling of whitespace and proper processing of SQL comments at some point in the near future, perhaps before the final 1.7.2 release. In any event, 1.7.2 now correctly processes the following JDBC escape forms to arbitrary nesting depth, but only if the exact whitespace layout described below is used:

  1. {call ...}
  2. {?= call ...}
  3. {fn ...}
  4. {oj ...}
  5. {d ...}
  6. {t ...}
  7. {ts ...}

Specified by:
nativeSQL in interface Connection
Parameters:
sql - a SQL statement that may contain one or more '?' parameter placeholders
Returns:
the native form of this statement
Throws:
SQLException - if a database access error occurs


setAutoCommit

public void setAutoCommit(boolean autoCommit)
                   throws SQLException
Sets this connection's auto-commit mode to the given state. If a connection is in auto-commit mode, then all its SQL statements will be executed and committed as individual transactions. Otherwise, its SQL statements are grouped into transactions that are terminated by a call to either the method commit or the method rollback. By default, new connections are in auto-commit mode.

The commit occurs when the statement completes or the next execute occurs, whichever comes first. In the case of statements returning a ResultSet object, the statement completes when the last row of the ResultSet object has been retrieved or the ResultSet object has been closed. In advanced cases, a single statement may return multiple results as well as output parameter values. In these cases, the commit occurs when all results and output parameter values have been retrieved.

NOTE: If this method is called during a transaction, the transaction is committed.

HSQLDB-Specific Information:

Up to and including HSQLDB 1.7.2,

  1. All rows of a result set are retrieved internally before the first row can actually be fetched.
    Therefore, a statement can be considered complete as soon as any XXXStatement.executeXXX method returns.
  2. Multiple result sets and output parameters are not yet supported.

(boucherb@users)

Specified by:
setAutoCommit in interface Connection
Parameters:
autoCommit - true to enable auto-commit mode; false to disable it
Throws:
SQLException - if a database access error occurs
See Also:
getAutoCommit()

getAutoCommit

public boolean getAutoCommit()
                      throws SQLException
Gets the current auto-commit state.

Specified by:
getAutoCommit in interface Connection
Returns:
the current state of auto-commit mode
Throws:
SQLException - Description of the Exception
See Also:
setAutoCommit(boolean)

commit

public void commit()
            throws SQLException
Makes all changes made since the previous commit/rollback permanent and releases any database locks currently held by the Connection. This method should be used only when auto-commit mode has been disabled.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, savepoints are supported both in SQL and via the JDBC interface.

Using SQL, savepoints may be set, released and used in rollback as follows:

 SAVEPOINT <savepoint-name>
 RELEASE SAVEPOINT <savepoint-name>
 ROLLBACK TO SAVEPOINT <savepoint-name>
 

Specified by:
commit in interface Connection
Throws:
SQLException - if a database access error occurs
See Also:
setAutoCommit(boolean)

rollback

public void rollback()
              throws SQLException
Drops all changes made since the previous commit/rollback and releases any database locks currently held by this Connection. This method should be used only when auto- commit has been disabled.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, savepoints are fully supported both in SQL and via the JDBC interface.

Using SQL, savepoints may be set, released and used in rollback as follows:

 SAVEPOINT <savepoint-name>
 RELEASE SAVEPOINT <savepoint-name>
 ROLLBACK TO SAVEPOINT <savepoint-name>
 

Specified by:
rollback in interface Connection
Throws:
SQLException - if a database access error occurs
See Also:
setAutoCommit(boolean)

close

public void close()
           throws SQLException
Releases this Connection object's database and JDBC resources immediately instead of waiting for them to be automatically released.

Calling the method close on a Connection object that is already closed is a no-op.

Note: A Connection object is automatically closed when it is garbage collected. Certain fatal errors also close a Connection object.

HSQLDB-Specific Information:

In 1.7.2, INTERNAL Connection objects are not closable from JDBC client code.

Specified by:
close in interface Connection
Throws:
SQLException - if a database access error occurs

isClosed

public boolean isClosed()
Tests to see if a Connection is closed.

Specified by:
isClosed in interface Connection
Returns:
true if the connection is closed; false if it's still open

getMetaData

public DatabaseMetaData getMetaData()
                             throws SQLException
Gets the metadata regarding this connection's database. A Connection's database is able to provide information describing its tables, its supported SQL grammar, its stored procedures, the capabilities of this connection, and so on. This information is made available through a DatabaseMetaData object.

HSQLDB-Specific Information:

JDBC DatabaseMetaData methods returning ResultSet were not implemented fully before 1.7.2. Some of these methods always returned empty result sets. Other methods did not accurately reflect all of the MetaData for the category. Also, some method ignored the filters provided as parameters, returning an unfiltered result each time.

Also, the majority of methods returning ResultSet threw an SQLException when accessed by a non-admin user.


Starting with HSQLDB 1.7.2, essentially full database metadata is supported.

For discussion in greater detail, please follow the link to the overview for jdbcDatabaseMetaData, below.

Specified by:
getMetaData in interface Connection
Returns:
a DatabaseMetaData object for this Connection
Throws:
SQLException - if a database access error occurs
See Also:
jdbcDatabaseMetaData

setReadOnly

public void setReadOnly(boolean readonly)
                 throws SQLException
Puts this connection in read-only mode as a hint to enable database optimizations.

Note: This method should not be called while in the middle of a transaction.

HSQLDB-Specific Information:

Up to and including 1.7.2, HSQLDB will commit the current transaction automatically when this method is called.

Additionally, HSQLDB provides a way to put a whole database in read-only mode. This is done by manually adding the line 'readonly=true' to the database's .properties file while the database is offline. Upon restart, all connections will be readonly, since the entire database will be readonly. To take a database out of readonly mode, simply take the database offline and remove the line 'readonly=true' from the database's .properties file. Upon restart, the database will be in regular (read-write) mode.

When a database is put in readonly mode, its files are opened in readonly mode, making it possible to create CD-based readonly databases. To create a CD-based readonly database that has CACHED tables and whose .data file is suspected of being highly fragmented, it is recommended that the database first be SHUTDOWN COMPACTed before copying the database files to CD. This will reduce the space required and may improve access times against the .data file which holds the CACHED table data.

Starting with 1.7.2, an alternate approach to opimizing the .data file before creating a CD-based readonly database is to issue the CHECKPOINT DEFRAG command followed by SHUTDOWN to take the database offline in preparation to burn the database files to CD.

Specified by:
setReadOnly in interface Connection
Parameters:
readonly - The new readOnly value
Throws:
SQLException - if a database access error occurs

isReadOnly

public boolean isReadOnly()
                   throws SQLException
Tests to see if the connection is in read-only mode.

Specified by:
isReadOnly in interface Connection
Returns:
true if connection is read-only and false otherwise
Throws:
SQLException - if a database access error occurs

setCatalog

public void setCatalog(String catalog)
                throws SQLException
Sets a catalog name in order to select a subspace of this Connection's database in which to work.

HSQLDB-Specific Information:

HSQLDB does not yet support catalogs and simply ignores this request.

Specified by:
setCatalog in interface Connection
Parameters:
catalog - the name of a catalog (subspace in this Connection object's database) in which to work (Ignored)
Throws:
SQLException - if a database access error occurs


getCatalog

public String getCatalog()
                  throws SQLException
Returns the Connection's current catalog name.

HSQLDB-Specific Information:

HSQLDB does not yet support catalogs and always returns null.

Specified by:
getCatalog in interface Connection
Returns:
the current catalog name or null

For HSQLDB, this is always null.

Throws:
SQLException - Description of the Exception

setTransactionIsolation

public void setTransactionIsolation(int level)
                             throws SQLException
Attempts to change the transaction isolation level for this Connection object to the one given. The constants defined in the interface Connection are the possible transaction isolation levels.

Note: If this method is called during a transaction, the result is implementation-defined.

HSQLDB-Specific Information:

Up to and including 1.7.1, HSQLDB supports only Connection.TRANSACTION_READ_UNCOMMITTED.

Specified by:
setTransactionIsolation in interface Connection
Parameters:
level - one of the following Connection constants: Connection.TRANSACTION_READ_UNCOMMITTED , Connection.TRANSACTION_READ_COMMITTED, Connection.TRANSACTION_REPEATABLE_READ, or Connection.TRANSACTION_SERIALIZABLE. (Note that Connection.TRANSACTION_NONE cannot be used because it specifies that transactions are not supported.)
Throws:
SQLException - if a database access error occurs or the given parameter is not one of the Connection constants

See Also:
jdbcDatabaseMetaData.supportsTransactionIsolationLevel(int), getTransactionIsolation()

getTransactionIsolation

public int getTransactionIsolation()
                            throws SQLException
Retrieves this Connection object's current transaction isolation level.

HSQLDB-Specific Information:

HSQLDB always returns Connection.TRANSACTION_READ_UNCOMMITED.

Specified by:
getTransactionIsolation in interface Connection
Returns:
the current transaction isolation level, which will be one of the following constants: Connection.TRANSACTION_READ_UNCOMMITTED , Connection.TRANSACTION_READ_COMMITTED, Connection.TRANSACTION_REPEATABLE_READ, Connection.TRANSACTION_SERIALIZABLE, or Connection.TRANSACTION_NONE

Up to and including 1.7.1, TRANSACTION_READ_UNCOMMITTED is always returned

Throws:
SQLException - if a database access error occurs

See Also:
jdbcDatabaseMetaData.supportsTransactionIsolationLevel(int), setTransactionIsolation

getWarnings

public SQLWarning getWarnings()
                       throws SQLException
Retrieves the first warning reported by calls on this Connection object. If there is more than one warning, subsequent warnings will be chained to the first one and can be retrieved by calling the method SQLWarning.getNextWarning on the warning that was retrieved previously.

This method may not be called on a closed connection; doing so will cause an SQLException to be thrown.

Note: Subsequent warnings will be chained to this SQLWarning.

HSQLDB-Specific Information:

Starting with 1.7.2, HSQLDB produces warnings whenever a createStatement(), prepareStatement() or prepareCall() invocation requests an unsupported but defined combination of result set type, concurrency and holdability, such that another set is substituted.

Specified by:
getWarnings in interface Connection
Returns:
the first SQLWarning object or null if there are none

Throws:
SQLException - if a database access error occurs or this method is called on a closed connection

See Also:
SQLWarning

clearWarnings

public void clearWarnings()
                   throws SQLException
Clears all warnings reported for this Connection object. After a call to this method, the method getWarnings returns null until a new warning is reported for this Connection.

HSQLDB-Specific Information:

Before HSQLDB 1.7.2, SQLWarning was not supported, and calls to this method are simply ignored.

Starting with HSQLDB 1.7.2, the standard behaviour is implemented.

Specified by:
clearWarnings in interface Connection
Throws:
SQLException - if a database access error occurs


createStatement

public Statement createStatement(int type,
                                 int concurrency)
                          throws SQLException
Creates a Statement object that will generate ResultSet objects with the given type and concurrency. This method is the same as the createStatement method above, but it allows the default result set type and result set concurrency type to be overridden.

HSQLDB-Specific Information:

Up to HSQLDB 1.6.1, support was provided only for type TYPE_FORWARD_ONLY and concurrency CONCUR_READ_ONLY.

Starting with HSQLDB 1.7.0, support is now provided for types TYPE_FORWARD_ONLY, and TYPE_SCROLL_INSENSITIVE, with concurrency CONCUR_READ_ONLY. Starting with HSQLDB 1.7.2, the behaviour regarding the type and concurrency values has changed to more closely conform to the specification. That is, if an unsupported combination is requested, a SQLWarning is issued on this Connection and the closest supported combination is used instead.

Notes:

Up to 1.6.1, calling this method returned null if the connection was already closed and a supported combination of type and concurrency was specified. This was possibly counter-intuitive to the expectation that an exception would be thrown for closed connections. Starting with 1.7.0. the behaviour is to throw a SQLException if the connection is closed.

Specified by:
createStatement in interface Connection
Parameters:
type - a result set type; one of ResultSet.TYPE_FORWARD_ONLY, ResultSet.TYPE_SCROLL_INSENSITIVE, or ResultSet.TYPE_SCROLL_SENSITIVE (not supported)
concurrency - a concurrency type; one of ResultSet.CONCUR_READ_ONLY or ResultSet.CONCUR_UPDATABLE (not supported)
Returns:
a new Statement object that will, within the release-specific documented limitations of support, generate ResultSet objects with the given type and concurrency
Throws:
SQLException - if a database access error occurs or the given parameters are not ResultSet constants indicating a supported type and concurrency
Since:
JDK 1.2 (JDK 1.1.x developers: read the new overview for jdbcConnection)

prepareStatement

public PreparedStatement prepareStatement(String sql,
                                          int type,
                                          int concurrency)
                                   throws SQLException
Creates a PreparedStatement object that will generate ResultSet objects with the given type and concurrency. This method is the same as the prepareStatement method above, but it allows the default result set type and result set concurrency type to be overridden.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, the behaviour regarding the type and concurrency values has changed to more closely conform to the specification. That is, if an unsupported combination is requested, a SQLWarning is issued on this Connection and the closest supported combination is used instead.

Also starting with 1.7.2, the support for and behaviour of PreparedStatment has changed. Please read the introductory section of the documentation for org.hsqldb.jdbcPreparedStatement.

Specified by:
prepareStatement in interface Connection
Parameters:
sql - a String object that is the SQL statement to be sent to the database; may contain one or more ? IN parameters
type - a result set type; one of ResultSet.TYPE_FORWARD_ONLY, ResultSet.TYPE_SCROLL_INSENSITIVE, or ResultSet.TYPE_SCROLL_SENSITIVE (not supported)
concurrency - a concurrency type; one of ResultSet.CONCUR_READ_ONLY or ResultSet.CONCUR_UPDATABLE (not supported)
Returns:
a new PreparedStatement object containing the pre-compiled SQL statement that will produce ResultSet objects with the given type and concurrency
Throws:
SQLException - if a database access error occurs or the given parameters are not ResultSet constants indicating a supported type and concurrency
Since:
JDK 1.2 (JDK 1.1.x developers: read the new overview for jdbcConnection)

prepareCall

public CallableStatement prepareCall(String sql,
                                     int resultSetType,
                                     int resultSetConcurrency)
                              throws SQLException
Creates a CallableStatement object that will generate ResultSet objects with the given type and concurrency. This method is the same as the prepareCall method above, but it allows the default result set type and result set concurrency type to be overridden.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, the behaviour regarding the type, concurrency and holdability values has changed to more closely conform to the specification. That is, if an unsupported combination is requrested, a SQLWarning is issued on this Connection and the closest supported combination is used instead.

Also starting with 1.7.2, the support for and behaviour of CallableStatement has changed. Please read the introdutory section of the documentation for org.hsqldb.jdbcCallableStatement.

Specified by:
prepareCall in interface Connection
Parameters:
sql - a String object that is the SQL statement to be sent to the database; may contain one or more ? parameters
resultSetType - a result set type; one of ResultSet.TYPE_FORWARD_ONLY, ResultSet.TYPE_SCROLL_INSENSITIVE, (not supported) or ResultSet.TYPE_SCROLL_SENSITIVE (not supported)
resultSetConcurrency - a concurrency type; one of ResultSet.CONCUR_READ_ONLY or ResultSet.CONCUR_UPDATABLE (not supported)
Returns:
a new CallableStatement object containing the pre-compiled SQL statement
Throws:
SQLException - if a database access error occurs or the given parameters are not ResultSet constants indicating a supported type and concurrency
Since:
JDK 1.2 (JDK 1.1.x developers: read the new overview for jdbcConnection)

getTypeMap

public Map getTypeMap()
               throws SQLException
Gets the type map object associated with this connection. Unless the application has added an entry to the type map, the map returned will be empty.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature. Calling this method always throws a SQLException, stating that the function is not supported.

Specified by:
getTypeMap in interface Connection
Returns:
the java.util.Map object associated with this Connection object
Throws:
SQLException - if a database access error occurs (always, up to HSQLDB 1.7.0, inclusive)
Since:
JDK 1.2 (JDK 1.1.x developers: read the new overview for jdbcConnection)

setTypeMap

public void setTypeMap(Map map)
                throws SQLException
Installs the given TypeMap object as the type map for this Connection object. The type map will be used for the custom mapping of SQL structured types and distinct types.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature. Calling this method always throws a SQLException, stating that the function is not supported.

Specified by:
setTypeMap in interface Connection
Parameters:
map - the java.util.Map object to install as the replacement for this Connection object's default type map
Throws:
SQLException - if a database access error occurs or the given parameter is not a java.util.Map object (always, up to HSQLDB 1.7.0, inclusive)
Since:
JDK 1.2 (JDK 1.1.x developers: read the new overview for jdbcConnection)
See Also:
getTypeMap()

setHoldability

public void setHoldability(int holdability)
                    throws SQLException
Changes the holdability of ResultSet objects created using this Connection object to the given holdability.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, this feature is supported.

As of 1.7.2, only HOLD_CURSORS_OVER_COMMIT is supported; supplying any other value will throw an exception.

Specified by:
setHoldability in interface Connection
Parameters:
holdability - a ResultSet holdability constant; one of ResultSet.HOLD_CURSORS_OVER_COMMIT or ResultSet.CLOSE_CURSORS_AT_COMMIT
Throws:
SQLException - if a database access occurs, the given parameter is not a ResultSet constant indicating holdability, or the given holdability is not supported
Since:
JDK 1.4, HSQLDB 1.7
See Also:
getHoldability(), ResultSet

getHoldability

public int getHoldability()
                   throws SQLException
Retrieves the current holdability of ResultSet objects created using this Connection object.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, this feature is supported.

Calling this method always returns HOLD_CURSORS_OVER_COMMIT.

Specified by:
getHoldability in interface Connection
Returns:
the holdability, one of ResultSet.HOLD_CURSORS_OVER_COMMIT or ResultSet.CLOSE_CURSORS_AT_COMMIT
Throws:
SQLException - if a database access occurs
Since:
JDK 1.4, HSQLDB 1.7
See Also:
setHoldability(int), ResultSet

setSavepoint

public Savepoint setSavepoint()
                       throws SQLException
Creates an unnamed savepoint in the current transaction and returns the new Savepoint object that represents it.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws a SQLException, stating that the function is not supported.

Specified by:
setSavepoint in interface Connection
Returns:
the new Savepoint object
Throws:
SQLException - if a database access error occurs or this Connection object is currently in auto-commit mode
Since:
JDK 1.4, HSQLDB 1.7
See Also:
jdbcSavepoint, Savepoint

setSavepoint

public Savepoint setSavepoint(String name)
                       throws SQLException
Creates a savepoint with the given name in the current transaction and returns the new Savepoint object that represents it.

HSQLDB-Specific Information:

Specified by:
setSavepoint in interface Connection
Parameters:
name - a String containing the name of the savepoint
Returns:
the new Savepoint object
Throws:
SQLException - if a database access error occurs or this Connection object is currently in auto-commit mode
Since:
JDK 1.4, HSQLDB 1.7
See Also:
jdbcSavepoint, Savepoint

rollback

public void rollback(Savepoint savepoint)
              throws SQLException
Undoes all changes made after the given Savepoint object was set.

This method should be used only when auto-commit has been disabled.

HSQLDB-Specific Information:

Specified by:
rollback in interface Connection
Parameters:
savepoint - the Savepoint object to roll back to
Throws:
SQLException - if a database access error occurs, the Savepoint object is no longer valid, or this Connection object is currently in auto-commit mode
Since:
JDK 1.4, HSQLDB 1.7
See Also:
jdbcSavepoint, Savepoint, rollback()

releaseSavepoint

public void releaseSavepoint(Savepoint savepoint)
                      throws SQLException
Removes the given Savepoint object from the current transaction. Any reference to the savepoint after it have been removed will cause an SQLException to be thrown.

HSQLDB-Specific Information:

Specified by:
releaseSavepoint in interface Connection
Parameters:
savepoint - the Savepoint object to be removed
Throws:
SQLException - if a database access error occurs or the given Savepoint object is not a valid savepoint in the current transaction
Since:
JDK 1.4, HSQLDB 1.7
See Also:
jdbcSavepoint, Savepoint

createStatement

public Statement createStatement(int resultSetType,
                                 int resultSetConcurrency,
                                 int resultSetHoldability)
                          throws SQLException
Creates a Statement object that will generate ResultSet objects with the given type, concurrency, and holdability. This method is the same as the createStatement method above, but it allows the default result set type, concurrency, and holdability to be overridden.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, this feature is supported.

Starting with HSQLDB 1.7.2, the behaviour regarding the type, concurrency and holdability values has changed to more closely conform to the specification. That is, if an unsupported combination is requested, a SQLWarning is issued on this Connection and the closest supported combination is used instead.

Specified by:
createStatement in interface Connection
Parameters:
resultSetType - one of the following ResultSet constants: ResultSet.TYPE_FORWARD_ONLY, ResultSet.TYPE_SCROLL_INSENSITIVE, or ResultSet.TYPE_SCROLL_SENSITIVE
resultSetConcurrency - one of the following ResultSet constants: ResultSet.CONCUR_READ_ONLY or ResultSet.CONCUR_UPDATABLE
resultSetHoldability - one of the following code>ResultSet constants: ResultSet.HOLD_CURSORS_OVER_COMMIT or ResultSet.CLOSE_CURSORS_AT_COMMIT
Returns:
a new Statement object that will generate ResultSet objects with the given type, concurrency, and holdability
Throws:
SQLException - if a database access error occurs or the given parameters are not ResultSet constants indicating type, concurrency, and holdability
Since:
JDK 1.4, HSQLDB 1.7
See Also:
ResultSet

prepareStatement

public PreparedStatement prepareStatement(String sql,
                                          int resultSetType,
                                          int resultSetConcurrency,
                                          int resultSetHoldability)
                                   throws SQLException
Creates a PreparedStatement object that will generate ResultSet objects with the given type, concurrency, and holdability.

This method is the same as the prepareStatement method above, but it allows the default result set type, concurrency, and holdability to be overridden.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, this feature is supported.

Starting with HSQLDB 1.7.2, the behaviour regarding the type, concurrency and holdability values has changed to more closely conform to the specification. That is, if an unsupported combination is requested, a SQLWarning is issued on this Connection and the closest supported combination is used instead.

Also starting with 1.7.2, the support for and behaviour of PreparedStatment has changed. Please read the introductory section of the documentation for org.hsqldb.jdbcPreparedStatement.

Specified by:
prepareStatement in interface Connection
Parameters:
sql - a String object that is the SQL statement to be sent to the database; may contain one or more ? IN parameters
resultSetType - one of the following ResultSet constants: ResultSet.TYPE_FORWARD_ONLY, ResultSet.TYPE_SCROLL_INSENSITIVE, or ResultSet.TYPE_SCROLL_SENSITIVE
resultSetConcurrency - one of the following ResultSet constants: ResultSet.CONCUR_READ_ONLY or ResultSet.CONCUR_UPDATABLE
resultSetHoldability - one of the following ResultSet constants: ResultSet.HOLD_CURSORS_OVER_COMMIT or ResultSet.CLOSE_CURSORS_AT_COMMIT
Returns:
a new PreparedStatement object, containing the pre-compiled SQL statement, that will generate ResultSet objects with the given type, concurrency, and holdability
Throws:
SQLException - if a database access error occurs or the given parameters are not ResultSet constants indicating type, concurrency, and holdability
Since:
JDK 1.4, HSQLDB 1.7
See Also:
ResultSet

prepareCall

public CallableStatement prepareCall(String sql,
                                     int resultSetType,
                                     int resultSetConcurrency,
                                     int resultSetHoldability)
                              throws SQLException
Creates a CallableStatement object that will generate ResultSet objects with the given type and concurrency. This method is the same as the prepareCall method above, but it allows the default result set type, result set concurrency type and holdability to be overridden.

HSQLDB-Specific Information:

Starting with HSQLDB 1.7.2, this feature is supported.

Starting with HSQLDB 1.7.2, the behaviour regarding the type, concurrency and holdability values has changed to more closely conform to the specification. That is, if an unsupported combination is requrested, a SQLWarning is issued on this Connection and the closest supported combination is used instead.

Also starting with 1.7.2, the support for and behaviour of CallableStatment has changed. Please read the introdutory section of the documentation for org.hsqldb.jdbcCallableStatement.

Specified by:
prepareCall in interface Connection
Parameters:
sql - a String object that is the SQL statement to be sent to the database; may contain on or more ? parameters
resultSetType - one of the following ResultSet constants: ResultSet.TYPE_FORWARD_ONLY, ResultSet.TYPE_SCROLL_INSENSITIVE, or ResultSet.TYPE_SCROLL_SENSITIVE
resultSetConcurrency - one of the following ResultSet constants: ResultSet.CONCUR_READ_ONLY or ResultSet.CONCUR_UPDATABLE
resultSetHoldability - one of the following ResultSet constants: ResultSet.HOLD_CURSORS_OVER_COMMIT or ResultSet.CLOSE_CURSORS_AT_COMMIT
Returns:
a new CallableStatement object, containing the pre-compiled SQL statement, that will generate ResultSet objects with the given type, concurrency, and holdability
Throws:
SQLException - if a database access error occurs or the given parameters are not ResultSet constants indicating type, concurrency, and holdability
Since:
JDK 1.4, HSQLDB 1.7
See Also:
ResultSet

prepareStatement

public PreparedStatement prepareStatement(String sql,
                                          int autoGeneratedKeys)
                                   throws SQLException
Creates a default PreparedStatement object that has the capability to retrieve auto-generated keys. The given constant tells the driver whether it should make auto-generated keys available for retrieval. This parameter is ignored if the SQL statement is not an INSERT statement.

Note: This method is optimized for handling parametric SQL statements that benefit from precompilation. If the driver supports precompilation, the method prepareStatement will send the statement to the database for precompilation. Some drivers may not support precompilation. In this case, the statement may not be sent to the database until the PreparedStatement object is executed. This has no direct effect on users; however, it does affect which methods throw certain SQLExceptions.

Result sets created using the returned PreparedStatement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws a SQLException, stating that the function is not supported.

Specified by:
prepareStatement in interface Connection
Parameters:
sql - an SQL statement that may contain one or more '?' IN parameter placeholders
autoGeneratedKeys - a flag indicating that auto-generated keys should be returned, one of code>Statement.RETURN_GENERATED_KEYS or Statement.NO_GENERATED_KEYS.
Returns:
a new PreparedStatement object, containing the pre-compiled SQL statement, that will have the capability of returning auto-generated keys
Throws:
SQLException - if a database access error occurs or the given parameter is not a Statement constant indicating whether auto-generated keys should be returned
Since:
JDK 1.4, HSQLDB 1.7

prepareStatement

public PreparedStatement prepareStatement(String sql,
                                          int[] columnIndexes)
                                   throws SQLException
Creates a default PreparedStatement object capable of returning the auto-generated keys designated by the given array. This array contains the indexes of the columns in the target table that contain the auto-generated keys that should be made available. This array is ignored if the SQL statement is not an INSERT statement.

An SQL statement with or without IN parameters can be pre-compiled and stored in a PreparedStatement object. This object can then be used to efficiently execute this statement multiple times.

Note: This method is optimized for handling parametric SQL statements that benefit from precompilation. If the driver supports precompilation, the method prepareStatement will send the statement to the database for precompilation. Some drivers may not support precompilation. In this case, the statement may not be sent to the database until the PreparedStatement object is executed. This has no direct effect on users; however, it does affect which methods throw certain SQLExceptions.

Result sets created using the returned PreparedStatement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws a SQLException, stating that the function is not supported.

Specified by:
prepareStatement in interface Connection
Parameters:
sql - an SQL statement that may contain one or more '?' IN parameter placeholders
columnIndexes - an array of column indexes indicating the columns that should be returned from the inserted row or rows
Returns:
a new PreparedStatement object, containing the pre-compiled statement, that is capable of returning the auto-generated keys designated by the given array of column indexes
Throws:
SQLException - if a database access error occurs
Since:
JDK 1.4, HSQLDB 1.7

prepareStatement

public PreparedStatement prepareStatement(String sql,
                                          String[] columnNames)
                                   throws SQLException
Creates a default PreparedStatement object capable of returning the auto-generated keys designated by the given array. This array contains the names of the columns in the target table that contain the auto-generated keys that should be returned. This array is ignored if the SQL statement is not an INSERT statement.

An SQL statement with or without IN parameters can be pre-compiled and stored in a PreparedStatement object. This object can then be used to efficiently execute this statement multiple times.

Note: This method is optimized for handling parametric SQL statements that benefit from precompilation. If the driver supports precompilation, the method prepareStatement will send the statement to the database for precompilation. Some drivers may not support precompilation. In this case, the statement may not be sent to the database until the PreparedStatement object is executed. This has no direct effect on users; however, it does affect which methods throw certain SQLExceptions.

Result sets created using the returned PreparedStatement object will by default be type TYPE_FORWARD_ONLY and have a concurrency level of CONCUR_READ_ONLY.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws a SQLException, stating that the function is not supported.

Specified by:
prepareStatement in interface Connection
Parameters:
sql - an SQL statement that may contain one or more '?' IN parameter placeholders
columnNames - an array of column names indicating the columns that should be returned from the inserted row or rows
Returns:
a new PreparedStatement object, containing the pre-compiled statement, that is capable of returning the auto-generated keys designated by the given array of column names
Throws:
SQLException - if a database access error occurs
Since:
JDK 1.4, HSQLDB 1.7

finalize

public void finalize()
The default implementation simply attempts to silently close() this Connection



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