|PostgreSQL Reference Manual - Volume 2 - Programming Guide|
by The PostgreSQL Global Development Group
Paperback (6"x9"), 408 pages
RRP £19.95 ($34.95)
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3.9 Informix compatibility mode
ecpg can be run in a so-called Informix compatibility mode. If
this mode is active, it tries to behave as if it were the Informix
precompiler for Informix E/SQL. Generally spoken this will allow you to use
the dollar sign instead of the
EXEC SQL primitive to introduce
embedded SQL commands.
$int j = 3; $CONNECT TO :dbname; $CREATE TABLE test(i INT PRIMARY KEY, j INT); $INSERT INTO test(i, j) VALUES (7, :j); $COMMIT;
There are two compatiblity modes: INFORMIX, INFORMIX_SE
When linking programs that use this compatibility mode, remember to link
libcompat that is shipped with ecpg.
Besides the previously explained syntactic sugar, the Informix compatibility mode ports some functions for input, output and transformation of data as well as embedded SQL statements known from E/SQL to ecpg.
Informix compatibility mode is closely connected to the pgtypeslib library
of ecpg. pgtypeslib maps SQL data types to data types within the C host
program and most of the additional functions of the Informix compatibility
mode allow you to operate on those C host program types. Note however that
the extent of the compatibility is limited. It does not try to copy Informix
behaviour; it allows you to do more or less the same operations and gives
you functions that have the same name and the same basic behavior but it is
no drop-in replacement if you are using Informix at the moment. Moreover,
some of the data types are different. For example,
PostgreSQL's datetime and interval types do not
know about ranges like for example
YEAR TO MINUTE so you won't
find support in ecpg for that either.
|ISBN 0954612035||PostgreSQL Reference Manual - Volume 2 - Programming Guide||See the print edition|