POSTQUEL

POSTQUEL

POSTGRES QUERy Language. The language used by the POSTGRES database system.

["The Design of POSTGRES", M. Stonebraker et al, Proc ACM SIGMOD Conf, June 1986].

Version 4.0.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)
References in periodicals archive ?
The query language of POSTGRES is known as POSTQUEL. POSTGRES can also incorporate precompiled user-written code into its query processing through dynamic loading.
Since Illustra SQL is a significantly more complex language than POSTQUEL, some modest changes had to be made to the code to handle subqueries and other SQL-specific features.
We expect POSTGRES users to interact with databases primarily by using the set-oriented query language, POSTQUEL. Hence, inclusion of a query language, an optimizer and the corresponding run-time system was a primary design goal.
Then, we turn to a short description of POSTQUEL and fast path.
A user can assign values to attributes of base types in POSTQUEL by either specifying a constant or a function which returns the correct type, for example:
Arrays are supported in the POSTQUEL query language using the standard bracket notation, for example.
Composite types are supported in POSTQUEL by the concept of path expressions.
There are three different kinds of functions known to POSTGRES: C functions; operators; and POSTQUEL functions.
Hence, they have arbitrary semantics and can run arbitrary POSTQUEL commands during execution.
The third kind of function available in POSTGRES is POSTQUEL functions.
POSTQUEL functions can also have parameters, for example:
Like C function, POSTQUEL functions can have a specific class as an argument: