SQL Relational Databases

A SQL Relational Database is a set of information stored in tables with fields and registers, which support SQL commands.

Each database can have one or more tables. Each table is composed of fields (columns) and registers (rows). Typically, the fields are pre-defined and the project adds or reads one or more registers, according to the query condition.

AVEVA Edge uses Database Providers (ADO.NET) to interface with SQL Relational Databases. Database Providers are libraries developed to access data from different databases through SQL commands. The ADO.NET Provider for a specific database can be supplied by the operating system or by the database manufacturer.

The following picture illustrates how AVEVA Edge can interface with different databases using a different Database Provider for each database.

The previous picture shows some of the most popular ADO.NET Providers for databases. You can see that the Microsoft ADO.NET Provider for ODBC Drivers allows you to access the database through an ODBC driver; see Using ODBC Databases for information about how to use this provider. It is also possible that you do not have an ADO.NET provider, but an OLE DB provider is available. By using the Microsoft ADO.NET Provider for OLE DB you can get access to the database; the Microsoft Jet OLE DB provider gives access to applications in the Microsoft Office package by using this approach.

Note: It is important to note that AVEVA Edge provides the interface for ADO.NET Providers. However, the ADO.NET Providers and/or the ODBC Driver/OLE DB Provider must be supplied either by the operating system or by the database manufacturer. If your Connection String does not refer to a valid ADO.NET Provider, the OLE.DB Provider will be used.

Although most projects typically link to only one type of database, You have the flexibility to link each task to a specific database supported by a Database Provider. Furthermore, by using this architecture, you do not need to worry about the specific characteristics of each database (it is mostly handled by the Database Provider for each database or by the Database Gateway interface). Therefore, the project settings are mostly uniform, regardless of the specific database chosen by you.