December, 2010

In this article we will compare the performance of both most used inheritance types – Table-per-Hierarchy (TPH) and Table-per-Type (TPT), supported by LinqConnect starting from version 2.00. For a better understanding of these inheritance types, we will use the Model First approach when the object model is developed first and after that the database scheme is generated.

To develop an object model, the Entity Developer tool will be used.

Our tests are performed on the following object model:

We have a hierarchy of three entity classes: the base class Gadget and its descendants – MobilePhone and Netbook.
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• Introduction
• Collection with unique elements
• Two and more collections with the repeated elements
• Optimization of the query without obvious collection
• Oracle-specific SQL
• The Afterword

Introduction

Devart was the first company who shipped Entity Framework providers for Oracle, MySQL, PostgreSQL, SQLite. And now we remain the leader in supporting new versions and features of Entity Framework.

Continuing to improve support of Entity Framework v4 features, as it was described here, we have optimized generated SQL for our ADO.NET data providers – dotConnect for Oracle, dotConnect for MySQL, dotConnect for PostgreSQL, and dotConnect for SQLite.

SQL generation was significantly improved and simplified in Entity Framework 4. Most of these improvements can be used in third-party providers, but one aspect has been improved only for SqlClient. It is a conversion of IN expression in Entity SQL and Contains method for collections in LINQ to Entities.

New versions of our dotConnect implement this enhancement for both Entity Framework v4 and Entity Framework v1. Our EF v1 users can get optimized SQL for IN Entity SQL expressions, but LINQ to Entities doesn’t support Contains method for collections in EF v1.
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