CODEWITHSUNDEEP
sqlplsql
778812
778812

Reputation: 101

What means sign $ before values in pl/sql?

What means sign $ before values in pl/sql?

Upvotes: 0

Views: 178

Answers (1)

Jon Heller
Jon Heller

Reputation: 36832

$ in PL/SQL likely either means an Inquiry Directive or a Preprocessor Control Token. Those are tools for conditional compilation.

Some other uses of $ are for naming schema objects (but not for the first character), and for a regular expression anchor in a row pattern match element. The new 12c row pattern matching features adds some annoying ambiguity into even a simple lexical analysis of PL/SQL.

Here's an example with all 4 uses put together. This is valid code in 12c, although it doesn't do anything useful.

alter session set plsql_ccflags = 'inq_dir_test:1';

declare
    v_test number;
begin
    select $$inq_dir_test inq_dir_test$$
    into v_test
    from dual
    match_recognize(
        measures x.dummy dummy
        pattern(
            ^$|
            x{$$inq_dir_test}|
            x{$IF 1=1 $THEN 1 $END}
        )
        define x as (1=1)
    );
end;
/

Upvotes: 1

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