Overview

The Table Data Gateway provides efficient isolation of the SQL and low-level ADO.NET code from the business logic, encapsulating all database related code in the gateway classes. RapTier generates two gateway classes for every table and view in the database.

The <TableCodeName>Collection_Base  abstract class is regenerated every time RapTier generates code. It contains select, insert, update, delete, and record mapping methods for a single table or view.

The <TableCodeName>Collection class is generated only if it does not exist already. It extends the <TableCodeName>Collection_Base class and can be used to add custom functionality to the table gateway. For example, you may want to add a method that returns all users who live in a certain city.

C#:
public User[] GetCityUsers(string city)
{
    return GetAsArray("City='" + city + "'", null);
}

VB.NET:
Public Function GetCityUsers(city As String) As User()
    Return GetAsArray("City='" + city + "'", Nothing)
End Function

Calling Table Data Gateway methods

To call a table data gateway method perform the following steps:

• Create a new instance of the class that represents a connection to your database.
• Get the gateway object.
• Call the required method.
• Close the connection to the database. 

For more information about calling the standard gateway methods, see the following topics:

• Retrieving
• Inserting
• Updating
• Deleting
• Paging
• Using Transactions
• Calling Stored Procedures