Introduction of Embedded SQL and Pro*C in Oracle

The query language constructs of SQL described in the previous sections are suited for formulating
ad-hoc queries, data manipulation statements and simple PL/SQL blocks in simple, interactive
tools such as SQL*Plus. Many data management tasks, however, occur in sophisticated engineering applications and these tasks are too complex to be handled by such an interactive tool.

Data are generated and manipulated in computationally complex application programs that are written in a Third-Generation-Language (3GL), and which, therefore, need an interface to the database system. Furthermore, a majority of existing data-intensive engineering applications are written previously using an imperative programming language and now want to make use of the functionality of a database system, thus requiring an easy to use programming interface to the database system. Such an interface is provided in the form of

Embedded SQL, an embedding of SQL into various programming languages, such as C, C++,
Cobol, Fortran etc. Embedded SQL provides application programmers a suitable means to
combine the computing power of a programming language with the database manipulation and
management capabilities of the declarative query language SQL.

Since all these interfaces exhibit comparable functionalities, in the following we describe the
embedding of SQL in the programming language C. For this, we base our discussion on the Oracle interface to C, called Pro*C. The emphasis in this section is