The UseEnhancedSchemaTable connection string attribute was added in .NET Data Provider For Teradata 13.0, and has been depricated in 16.10. The default value for this property is true. When it is specified in a connection string, it will appear as:

Data Source=TeradataServer; User Id=tdc; Password=petabyte; UseEnhancedSchemaTable=true;

When UseEnhancedSchemaTable is true the following features are provided:

Retrieve additional metadata from the Advanced SQL Engine. This includes metadata such as IsKey and IsUnique. Refer to TdDataReader.GetSchemaTable method for further information.
The key of the tables will be displayed in the Visual Studio Data Set Designer.
SQL Server Business Intelligence Design Studio: Cubes can be created without manually specifying the key when the corresponding SQL table has been defined with a primary key.
All relationships between tables are displayed graphically in the Visual Studio Query Designer.

When UseEnhancedSchemaTable is false the provider will have the same behavior as in pre-13.0 releases, with the following exception.

TdCommandBuilder always acts as though UseEnhancedSchemaTable=true.
This means that the following features and restrictions always apply:

TdCommandBuilder requires that the table specified in the SELECT statement must be defined with a primary key or with a Unique column or index. This was not required in earlier releases of the provider.
The setting of the property DbCommandBuilder.ConflictOption will affect how the WHERE clause is constructed. In earlier releases, this property was ignored.
Enables the TdCommandBuilder to use the key of the table when constructing the WHERE clause of the UPDATE and DELETE statements. In earlier releases, all the columns of a row were used in the WHERE clause.

See Also