ASA Programming Guide
  Deploying Databases and Applications
    Deploying client applications
      Deploying ODBC clients

Deploying connection information

ODBC client connection information is generally deployed as an ODBC data source. You can deploy an ODBC data source in one of the following ways:

• Programmatically    Add a data source description to your end-user's Registry or ODBC initialization files.

• Manually    Provide your end-users with instructions, so that they can create an appropriate data source on their own machine.

  You create a data source manually using the ODBC Administrator, from the User DSN tab or the System DSN tab. The Adaptive Server Anywhere ODBC driver displays the configuration dialog for entering settings. Data source settings include the location of the database file, the name of the database server, as well as any start up parameters and other options.

This section provides you with the information you need to know for either approach.

Types of data source 

There are three kinds of data sources: User data sources, System data sources, and File data sources.

User data source definitions are stored in the part of the registry containing settings for the specific user currently logged on to the system. System data sources, however, are available to all users and to Windows services, which run regardless of whether a user is logged onto the system or not. Given a correctly configured System data source named MyApp, any user can use that ODBC connection by providing DSN=MyApp in the ODBC connection string.

File data sources are not held in the registry, but are held in a special directory. A connection string must provide a FileDSN connection parameter to use a File data source.

Data source registry entries 

Each user data source is identified to the system by registry entries.

You must enter a set of registry values in a particular registry key. For User data sources the key is as follows:

HKEY_CURRENT_USER\
   SOFTWARE\
      ODBC\
         ODBC.INI\
            userdatasourcename

For System data sources the key is as follows:

HKEY_LOCAL_MACHINE\
   SOFTWARE\
      ODBC\
         ODBC.INI\
            systemdatasourcename

The key contains a set of registry values, each of which corresponds to a connection parameter. For example, the ASA 9.0 Sample key corresponding to the ASA 9.0 Sample data source contains the following settings:

In these entries, path is the Adaptive Server Anywhere installation directory.

In addition, you must add the data source to the list of data sources in the registry. For User data sources, you use the following key:

HKEY_CURRENT_USER\
   SOFTWARE\
      ODBC\
         ODBC.INI\
            ODBC Data Sources

For System data sources, use the following key:

HKEY_LOCAL_MACHINE\
   SOFTWARE\
      ODBC\
         ODBC.INI\
            ODBC Data Sources.

The value associates each data source with an ODBC driver. The value name is the data source name, and the value data is the ODBC driver name. For example, the User data source installed by Adaptive Server Anywhere is named ASA 9.0 Sample, and has the following value:

Caution: ODBC settings are easily viewed    User data source configurations can contain sensitive database settings such as a user's ID and password. These settings are stored in the registry in plain text, and can be view using the Windows registry editors regedit.exe or regedt32.exe, which are provided by Microsoft with the operating system. You can choose to encrypt passwords, or require users to enter them on connecting.

Required and optional connection parameters 

You can identify the data source name in an ODBC configuration string in this manner,

DSN=userdatasourcename

When a DSN parameter is provided in the connection string, the Current User data source definitions in the Registry are searched, followed by System data sources. File data sources are searched only when FileDSN is provided in the ODBC connection string.

The following table illustrates the implications to the user and developer when a data source exists and is included in the application's connection string as a DSN or FileDSN parameter.

Driver={ODBCdrivername}

For more information on ODBC connections and configurations, see the following:

• Connecting to a Database.

• The Open Database Connectivity (ODBC) SDK, available from Microsoft.