LZDECOMP_L
Purpose
Uncompresses the Latin data that was compressed using the LZCOMP_L function.
Syntax
where:
|
Syntax element… |
Specifies… |
|
TD_SYSFNLIB |
the name of the database where the function is located. |
|
compressed_string |
Latin character data that was compressed using the LZCOMP_L function. |
Note: This function takes no arguments when used as part of the COMPRESS USING or DECOMPRESS USING phrases. For more information about the COMPRESS/DECOMPRESS phrase, see SQL Data Types and Literals.
ANSI Compliance
This is a Teradata extension to the ANSI SQL:2011 standard.
Argument Type and Rules
Expressions passed to this function must have a data type of VARBYTE(n), where the maximum supported size (n) is 64000.
The input to this function must be the output result of the LZCOMP_L function.
If you specify NULL as input, the function returns NULL.
Result Type
The result data type is VARCHAR(64000) CHARACTER SET LATIN.
Usage Notes
LZDECOMP_L takes Latin data that was compressed using the LZCOMP_L function, uncompresses it, and returns an uncompressed Latin character string as the result.
See http://zlib.net for information about the decompression algorithm used by LZDECOMP_L.
Although you can call the function directly, LZDECOMP_L is normally used with algorithmic compression (ALC) to uncompress table columns previously compressed with LZCOMP_L.
For more information about ALC, see “COMPRESS and DECOMPRESS Phrases” in SQL Data Types and Literals.
Example
In this example, the Latin values in the Description column are compressed using the LZCOMP_L function with ALC. The LZDECOMP_L function uncompresses the previously compressed values.
CREATE MULTISET TABLE Pendants
(ItemNo INTEGER,
Gem CHAR(10) UPPERCASE CHARACTER SET LATIN,
Description VARCHAR(1000) CHARACTER SET LATIN
COMPRESS USING TD_SYSFNLIB.LZCOMP_L
DECOMPRESS USING TD_SYSFNLIB.LZDECOMP_L);