17.10 - Implicit Numeric-to-UDT Conversion - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - Data Types and Literals

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1143-171K
Language
English (United States)
SQL Engine performs implicit Numeric-to-UDT conversions for the following operations:
  • UPDATE
  • INSERT
  • Passing arguments to stored procedures, external stored procedures, UDFs, and UDMs
  • Specific system operators and functions identified in other sections of this document, unless the DisableUDTImplCastForSysFuncOp field of the DBS Control Record is set to TRUE

Performing an implicit data type conversion requires that an appropriate cast definition (see Usage Notes) exists that specifies the AS ASSIGNMENT clause.

The source numeric type of the cast definition does not have to be an exact match to the source numeric type of the implicit conversion. Vantage can use an implicit cast definition that specifies a BYTEINT, SMALLINT, INTEGER, BIGINT, DECIMAL/NUMERIC, NUMBER, or REAL/FLOAT/DOUBLE target type.

If multiple implicit cast definitions exist for converting different numeric types to the UDT, SQL Engine uses the implicit cast definition for the numeric type with the highest precedence. The following list shows the precedence of numeric types in order from lowest to highest precedence:
  • BYTEINT
  • SMALLINT
  • INTEGER
  • BIGINT
  • DECIMAL/NUMERIC
  • NUMBER
  • REAL/FLOAT/DOUBLE

If no numeric-to-UDT implicit cast definitions exist, SQL Engine looks for other cast definitions that can substitute.

IF the following combination of implicit cast definitions exists … THEN SQL Engine
DATE-to-UDT Character-to-UDT  
X   uses the DATE-to-UDT implicit cast definition.
  X uses the character-to-UDT implicit cast definition.

The character type cannot be CLOB.

If multiple character-to-UDT implicit cast definitions exist, then SQL Engine returns an SQL error.

X X reports an error.

Substitutions are valid because Vantage can implicitly cast a numeric type to the substitute data type, and then use the implicit cast definition to cast from the substitute data type to the UDT.