Schema Collections

The Schema collections return metadata for the Advanced SQL Engine objects. The notable metadata columns for the User Defined Type (UDT) data type are:

Column Name	Description
COLUMN_TYPE or DATA_TYPE	Set to the UDT type name. For example ST_GEOMETRY.
PROVIDERDBTYPE	Set to DBNull.Value

Schema Table

The SQL Engine transforms all User Defined Types to predefined SQL data types, for example VarChar, before sending data to the Data Provider. The TdDataReader.SchemaTable returns result set metadata for the predefined SQL data type specified in the transform definition. The "SQL Data Type and Literals" manual describes the External Representation for User Defined Types and implicit or explicit transformation to predefined SQL data types.

Configuring Parameters

Input, Output or InputOutput parameters must be declared as predefined SQL data types, for example Clob or Blob. The implicit or explicit transform definition specifies the predefined SQL data type that must be used by applications to send data to or receive data from the SQL Engine. For details on transform definitions, see "CREATE Transform" in "SQL Data Definition Language" manual.

TdCommandBuilder Limitation

 TdCommandBuilder does not support columns or parameters of type UDT. The Data Provider will throw a TdException when

1. Creating a Update, Delete or Insert command for a SelectCommand containing a column of type UDT.
2. DeriveParameters for a Stored Procedure with one or more parameters of type UDT.

 

See Also

Data Type Mappings

Accessor Methods for Retrieving Data

Configuring Parameters and Parameter Data Types