Accessing SQL from a programming language

A database programmer must have access to a general purpose programming language for at least two reasons:

• Not all queries can be expressed in SQL.

  SQL does not provide the full expressive power of a general-purpose language

• Non-declarative actions cannot be done from within SQL.

  Non-delcatarive actions include printing a report, interacting with a user, and sending the results of a query to a GUI.

There are two approaches to accessing SQL from a general purpose programming language:

• Dynamic SQL

  A general purpose program can connect to and communicate with a database server using a collection of functions.

• Embedded SQL

  Provides a means by which program can interact with a database server. However, under embedded SQL:

  • The SQL statements are identified at compile time, and are translated into function calls.

  • At runtime, these function calls connect to the database using an API that provides dynamic SQL facilities (but may be specific to the database being used).