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Teradata.Client.Provider
Mapping Views and ViewColumns to Tables
.NET Data Provider for Teradata > Developer's Guide > ADO.NET Entity Provider for Teradata > Entity Provider Store Schemas > Mapping Views and ViewColumns to Tables
.NET CORE   This feature is not supported by the .NET Core implementation of the Data Provider.

The following sections discuss the purpose of the mapping of the View and ViewColumns and how to enable the mapping.

The Views and ViewColumns Problem

The information that is returned from the Store Schemas originates from the Teradata Data Dictionary. When a store schema is accessed by an application, the Entity Framework requires that the Entity Provider generate a query against the corresponding object in the Data Dictionary. Unfortunately, prior to Teradata Database 16.0, information on columns of views cannot be directly retrieved from any object in the Data Dictionary. When information about view columns is requested, pre-processing of data is required before it is returned to the application. The pre-processing that is required to gain access to information on the columns of views cannot be performed within the SQL query that is generated by the Entity Provider.

To work around this problem, starting with the .NET Data Provider for Teradata 13.11, the Entity Provider enables the user to map the Views and ViewColumns store schemas to tables. This mapping is done by adding entries into the application configuration file. When this option has been configured, the Entity Provider will use these tables when the Views and ViewColumns are accessed by the Visual Studio Entity Data Model (EDM) Wizard, or by an application that executes a query against an EDM of the Store Schemas.

The SchemaLoader utility is used to load the tables with the information that is needed by the Views and ViewColumns store schema.

Note that although this process is not strictly required when working with Teradata Database 16.0 or higher, performance, when retrieving Column information, will be much slower without it.

Steps to Enable Access to Views and ViewColumns Store Schema

There are two steps that need to be performed when enabling access to the Views and ViewColumns store schemas. These steps can be performed in any order.

In This Section

SchemaLoader Utility -- Loading the tables

Table Definitions

Recommendations When Mapping Store Schemas to Tables