ST_Geometry Type Syntax | Geospatial Data Types | Teradata Vantage - Syntax - Advanced SQL Engine - Teradata Database

[SYSUDTLIB.] ST_GEOMETRY
  [ ( maxlength ) ]
  [ INLINE LENGTH integer ]
  [ attribute [...] ]

SYSUDTLIB.

The name of the database in which all UDTs are created.

maxlength

A positive integer value followed by an optional multiplier.

maxlength specifies the maximum length of the data type in bytes. You can define a maximum length on a per instance basis. When specified, the data type is used in a manner analogous to the VARBYTE or BLOB data types.

The length specified only covers the actual data length. The actual storage sizes include additional header information.

The default value is approximately 16 MB.

You can find the actual size of ST_Geometry objects by using the DataSize system function.

INLINE LENGTH integer

A positive integer value which specifies the inline storage size. Data that is smaller than or equal to the inline storage size is stored inside the base row; otherwise, it is stored in a LOB subtable.

The inline length cannot be larger than maxlength.

The default value is approximately 10,000 bytes.

attribute

Appropriate data attributes.

An ST_GEOMETRY column supports the following attributes:

• NULL
• NOT NULL
• FORMAT
• TITLE
• NAMED
• DEFAULT NULL

For more information on using the data attributes, see Teradata Vantage™ - Data Types and Literals, B035-1143.

An ST_GEOMETRY column does not support column storage or column constraint attributes.

Usage Notes

You can use the optional INLINE LENGTH specification to specify the inline storage size. When the data is smaller than or equal to the inline storage size, it is stored inside the base row. Otherwise, the data is stored as a LOB (large object).

If the inline length is equal to the maximum length specified for the data type, the data type is treated as a non-LOB type. In this case, the performance may be better because there is no LOB overhead. You may see some performance improvement especially when the data type is used with UDFs.

You can use the maxlength together with the INLINE LENGTH options to improve space management for geospatial data by forcing smaller geometries to be stored inline as non-LOB values. This stores the geospatial data within the table row itself, rather than in a separate LOB subtable. Furthermore, by specifying a small inline length for small geometries, Teradata Database will reserve less space in the row, so more columns can be added to the table. Additionally, non-LOB geometries work with some load utilities that do not support LOBs.