VistaDB - Overview

This article is relevant to entity models that utilize the deprecated Visual Studio integration of Telerik Data Access. The current documentation of the Data Access framework is available here.

To use Telerik Data Access with VistaDB you need to install VistaDB 4.0 or 5.0 database and to register a developer license on the machine (per developer). This installs the neccessary assemblies and the ADO.NET data provider for VistaDB. VistaDB comes with a few restrictions:

• Transactions are very expensive operations in VistaDB and are not considered to be a best practice. In order to shield Telerik Data Access users from this hurdle, all connections to a VistaDB database are created using the VistaDBTransaction.TransactionMode.Ignore mode. This instructs the VistaDB engine to ignore all transactions. However, this can be overridden by explicitly specifying a value in the connection string, using the "TransactionMode = value" property.

• VistaDB has certain limitations on SQL that can be executed. Certain OQL and LINQ queries like those listed below, need to be rewritten:

  • ORDER BY in VistaDB may not use aggregates or computed columns like DATEPART(day,col) or SUM(col). Hence queries that order by a calculated value need to be rewritten. For example: from o in Orders orderby o.Freight * o.Id select o.
  • The CASE state cannot be used in a WHERE or ORDER BY clause.

Telerik Data Access has been tested with the 4.0.12.1 and 5.0 versions of VistaDB.

Type Mapping

The Type Mapping topic shows the default mapping from .NET types to VistaDB specific types.