DB2 Version 10.1 for Linux, UNIX, and Windows

Graphic strings

A graphic string is a sequence of bytes that represents double-byte character data. The length of the string is the number of double-byte characters in the sequence. If the length is zero, the value is called the empty string. This value should not be confused with the null value.

Graphic strings are not supported in a database defined with a single-byte code page.

Graphic strings are not checked to ensure that their values contain only double-byte character code points. (The exception to this rule is an application precompiled with the WCHARTYPE CONVERT option. In this case, validation does occur.) Rather, the database manager assumes that double-byte character data is contained in graphic data fields. The database manager does check that a graphic string value is an even number of bytes long.

NUL-terminated graphic strings found in C are handled differently, depending on the standards level of the precompile option. This data type cannot be created in a table. It can only be used to insert data into and retrieve data from the database.

Fixed-length graphic strings (GRAPHIC)

All values in a fixed-length graphic string column have the same length, which is determined by the length attribute of the column. The length attribute must be between 1 and 127, inclusive.

Varying-length graphic strings

There are two types of varying-length graphic string:

A VARGRAPHIC value can be up to 16 336 double-byte characters long.
A DBCLOB (double-byte character large object) value can be up to 1 073 741 823 double-byte characters long. A DBCLOB is used to store large DBCS character-based data (such as documents written with a single character set) and, therefore, has a DBCS code page associated with it.

Special restrictions apply to an expression that results in a varying-length graphic string whose maximum length is greater than 127 bytes. These restrictions are the same as those specified in Varying-length character strings.

Note: The LONG VARGRAPHIC data type continues to be supported but is deprecated, not recommended, and might be removed in a future release.