LOB in Teradata

It is possible to create functions which operate on large object data types. The following library functions exists to provide the ability use LOB's as function input or output:

• FNC_GetLobLength - acquire Lob length
• FNC_LobAppend - add to Lob in memory
• FNC_LobClose - close a context to a Lob
• FNC_LobOpen - open a context to a Lob
• FNC_LobRead - read some or all
• FNC_LobRef2Loc - convert a Lob Reference to a Locator 
• FNC_LobLoc2Ref - convert a Locator to a Lob Reference

Example :
The CREATE FUNCTION syntax permits BLOB's or CLOB's to be the data type of an argument or a return value

CREATE FUNCTION JPEG_CROP
(
Image BLOB AS LOCATOR 
Width INTEGER, 
Height INTEGER, 
X_Offset INTEGER, 
Y_Offset INTEGER
) 
RETURNS BLOB AS LOCATOR
LANGUAGE C
NO SQL
EXTERNAL;


No comments:

Post a Comment