Non-Key Data Types

Non-Key Data Types

This section discusses the internal storage formats of data types that cannot be indexed (used as Btrieve keys).

The Binary Large Object (BLOB) type provides support for binary data fields up to 2 GB in size. This type consists of 2 parts:

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an 8-byte header in the fixed-length portion of the record. The header contains a 4-byte integer that identifies the offset to the beginning of the data in the variable-length portion of the record, and a 4-byte integer that specifies the size of the data.

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the binary data itself is stored within the variable-length portion of the record. The size of all BLOB and CLOB fields must sum to 2 GB or less, because the offset pointer into the variable-length portion of the record is limited to 2 GB maximum offset. To store the maximum BLOB size of 2 GB, you may have only 1 BLOB or CLOB field defined in the record.

For additional information, see BINARY and LONGVARBINARY and Limitations on LONGVARCHAR and LONGVARBINARY.

The Character Large Object (CLOB) type provides support for character data fields up to 2 GB in size. This type consists of 2 parts:

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an 8-byte header in the fixed-length portion of the record. The header contains a 4-byte integer that identifies the offset to the beginning of the data in the variable-length portion of the record, and a 4-byte integer that specifies the size of the data.

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the character data itself is stored within the variable-length portion of the record. The size of all BLOB and CLOB fields must sum to 2 GB or less, because the offset pointer into the variable-length portion of the record is limited to 2 GB maximum offset. To store the maximum BLOB size of 2 GB, you may have only 1 BLOB or CLOB field defined in the record.

For additional information, see CHAR, VARCHAR, and LONGVARCHAR and Limitations on LONGVARCHAR and LONGVARBINARY.