16.10 - Restrictions - Teradata Database

Teradata Database SQL Data Types and Literals

prodname
Teradata Database
vrm_release
16.10
created_date
June 2017
category
Programming Reference
featnum
B035-1143-161K
  • You cannot use ALC to compress columns that have a data type of structured UDT.
  • The TD_LZ_COMPRESS and TD_LZ_DECOMPRESS system functions compress all large UDTs including UDT-based system types such as Geospatial, XML, and JSON. However, if you write your own compression functions, the following restrictions apply:
    • Custom compression functions cannot be used to compress UDT-based system types (except for ARRAY and Period types).
    • Custom compression functions cannot be used to compress distinct UDTs that are based on UDT-based system types (except for ARRAY and Period types).
  • You cannot write your own compression functions to perform algorithmic compression on JSON type columns. However, Teradata provides the JSON_COMPRESS and JSON_DECOMPRESS functions that you can use to perform ALC on JSON type columns.
  • You cannot use ALC to compress temporal columns:
    • A column defined as SYSTEM_TIME, VALIDTIME, or TRANSACTIONTIME.
    • The DateTime columns that define the beginning and ending bounds of a temporal derived period column (SYSTEM_TIME, VALIDTIME, or TRANSACTIONTIME).

    You can use ALC to compress period data types in columns that are nontemporal; however, you cannot use ALC to compress derived period columns.

    For details about temporal tables, see Temporal Table Support and ANSI Temporal Table Support.

  • You cannot specify multi-value or algorithmic compression for a row-level security constraint column.