LZDECOMP_L - Teradata Database

SQL Functions, Operators, Expressions, and Predicates

Product
Teradata Database
Release Number
15.00
Language
English (United States)
Last Update
2018-09-24
dita:id
B035-1145
lifecycle
previous
Product Category
Teradata® Database

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);