FirebirdSQL logo
 Window (Analytical) FunctionsContext Variables 

Function OPEN_BLOB

RDB$BLOB_UTIL.OPEN_BLOB opens an existing BLOB for reading.It returns a handle (an integer bound to the transaction) suitable for use with other functions of this package, like SEEK, READ_DATA and CLOSE_HANDLE.

Handles which are not explicitly closed are closed automatically when the transaction ends.

Input parameter

  • BLOB type BLOB NOT NULL

Return type: INTEGER NOT NULL.

Function READ_DATA

RDB$BLOB_UTIL.READ_DATA reads chunks of data of a BLOB handle opened with RDB$BLOB_UTIL.OPEN_BLOB.When the BLOB is fully read and there is no more data, it returns NULL.

If LENGTH is passed with a positive number, it returns a VARBINARY with its maximum length.

If LENGTH is NULL it returns a segment of the BLOB with a maximum length of 32765.

Input parameters

  • HANDLE type INTEGER NOT NULL

  • LENGTH type INTEGER

Return type: VARBINARY(32765).