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ASA SQL Reference
SQL Data Types
For storing strings of letters, numbers and symbols.
Adaptive Server Anywhere treats CHAR, VARCHAR, and LONG VARCHAR columns all as the same type. Values up to 254 characters are stored as short strings, with a preceding length byte. Any values that are longer than 255 bytes are considered long strings. Characters after the 255th byte are stored separately from the row containing the long string value.
There are several functions (see SQL Functions) that will ignore the part of any string past the 255th character. They are soundex, similar, and all of the date functions. Also, any arithmetic involving the conversion of a long string to a number will work on only the first 255 characters. It would be extremely unusual to run in to one of these limitations.
All other functions and all other operators work with the full length of long strings.
Character data is placed in the database using the exact binary representation that is passed from the application. This usually means that character data is stored in the database with the binary representation of the current code page. The code page is the character set representation used by IBM-compatible personal computers. You can find documentation about code pages in the documentation for your operating system.
Most code pages are the same for the first 128 characters. If you use special characters from the top half of the code page (accented international language characters), you must be careful with your databases. In particular, if you copy the database to a machine that uses a different code page, those special characters will be retrieved from the database using the original code page representation. With the new code page, they will appear on the screen to be the wrong characters.
This problem also appears if you have two clients using the same multi-user server, but run with different code pages. Data inserted or updated by one client may appear incorrect to the other.
This problem also shows up if a database is used across platforms. PowerBuilder and many other Windows applications insert data into the database in the standard ANSI character set. If non-Windows applications attempt to use this data, they will not properly display or update the extended characters.
This problem is quite complex. If any of your applications use the extended characters in the upper half of the code page, make sure that all clients and all machines using the database use the same or a compatible code page.
Data type lengths of less than one are not allowed.
The CHARACTER (n) alternative for CHAR is not supported in Adaptive Server Enterprise.
Adaptive Server Anywhere does not support the NCHAR and NVARCHAR data types provided by Adaptive Server Enterprise.
CHAR data type [Character]
CHARACTER VARYING (VARCHAR) data type [Character]
LONG VARCHAR data type [Character]
TEXT data type [Character]
UNIQUEIDENTIFIERSTR data type [Character]
XML data type [Character]