January 2002
Intermediate to advanced
640 pages
16h 39m
English
Content preview from Practical PostgreSQLBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Language Structure
The structure of PL/pgSQL is fairly simple, mainly due to the fact that each portion of code is designed to exist as a function. While it may not look immediately similar to other languages, PL/pgSQL’s structure is similar to other programming languages such as C, in which each portion of code acts (and is created) as a function, all variables must be declared before being used, and code segments accept arguments when called and return arguments at their end.
Regarding its syntax, PL/pgSQL functions are case insensitive. You can use mixed, upper-,
or lowercase for keywords and identifiers. Additionally, you will notice the use of pairs of
apostrophes (single quotes) in many places within this chapter. These are required whenever a
single apostrophe would ordinarily be used. The pair of apostrophes is a means to escape an
apostrophe within the function definition to PostgreSQL, since a function definition is
actually a large string constant within a CREATE FUNCTION statement.
This section will discuss the block organization of PL/pgSQL code, how to use comments, how PL/pgSQL expressions are organized, and the usage of statements.
Code Blocks
PL/pgSQL code is organized in blocks of code. This method of organization is known as
block structured code. Code blocks are entered within a SQL CREATE FUNCTION call that creates the PL/pgSQL function in the PostgreSQL
database. This CREATE FUNCTION command names the new function, states its argument types, and states the return ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.