ecpg - embedded SQL preprocessor for C

ecpg - embedded SQL preprocessor for C / PostgreSQL

.BR ecpg

[\c

.BR"-v"

]

[\c

.BR"-d"

]

[\c

.BR"-o"

outfile

]

file1

[file2]

[...]

.in-5n

\fBecpg\fR [-v ] [-t] [-I include-path ] [-o outfile ] file1 [ file2 ] [ ... ]

ecpg an embedded SQL in C package for PostgreSQL. It enables you to

develop C programs with embedded SQL code.

.B\fIecpg\fP

is an embedded SQL preprocessor for C / PostgreSQL. It

enables development of C programs with embedded SQL code.

.PP

.IR"ecpg"

understands the following command-line options:

.B\fIecpg\fP

is ultimately intended to be as compliant as possible with the

ANSI SQL-2 standard and existing commercial ESQL/C packages.

.B\fIecpg\fP

interprets the following flags when it is invoked

on the command line:

.PP

.PD0

.TP10

Print version information.

.PD

.TP

Print version information.

Turn off auto-transactin mode.

.PD

.TP

Turn on debugging.

.TP

Specifies that

.IR"ecpg"

should write all its output to

.IR"outfile". Ifno suchoption isgiven theoutput iswritten tofoo.c

if the input file was name foo.pgc or to foo.bar.c if the input file was

foo.bar.

Specify additional include path. Defaults are\.,

/usr/local/include, the PostgreSQL include path which is defined at compile

time (default: /usr/local/pgsql/lib), /usr/include

.PD

.TP

The files to be processed.

The return code is alway -1 in case of an error. You cannot see which error

occured by examining the return code.

Specifies that ecpg should write all its output to outfile.

If no such option is given the output is written to foo.c

(if the input file was named foo.pgc.)

If the input file was named foo.bar the output file will be

named foo.bar.c.

.PD

.TP

The files to be processed.

The

.B\fIecpg\fP

preprocessor is built during the PostgreSQL installation. Binaries and

libraries are installed into the PGBASE (i.e., /usr/local/pgsql/... )

subdirectories.

.B\fIecpg\fP

(-o file) file.pgc

.LP

The .pgc extension is an arbitrary means of denoting ecpg source.

Assuming the\fIPostgreSQL\fP binaries are in /usr/local/pgsql:

.LP

gcc -g -i /usr/local/pgsql/include (-o file) file.c

-L /usr/local/pgsql/lib -lecpg -lpq

.LP

.LP

The preprocessor will prepend two directives to the source:

.LP

\fI#include<ecpgtype.h>\fP and\fI#include<ecpglib.h>\fP

Variables declared within ecpg source code must be prepended with:

.LP

EXEC SQL BEGIN DECLARE SECTION;

.LP

Similarly, variable declaration sections must terminate with:

.LP

EXEC SQL END DECLARE SECTION;

.LP

NOTE: prior to version 2.1.0, each variable had to be declared

on a separate line. As of version 2.1.0 multiple variables may

be declared on a single line:

.LP

char foo(16), bar(16);

.LP

The SQL communication area is defined with:

.LP

EXEC SQL INCLUDE sqlca;

.LP

NOTE: the lowercase `sqlca'. While SQL convention may be

followed, i.e., using uppercase to separate embedded SQL

from C statements, sqlca (which includes the sqlca.h

header file) MUST be lowercase. This is because the EXEC SQL

prefix indicates that this INCLUDE will be parsed by ecpg.

ecpg observes case sensitivity (SQLCA.h will not be found.)

EXEC SQL INCLUDE can be used to include other header files

as long as case sensitivity is observed.

.LP

The sqlprint command is used with the EXEC SQL WHENEVER

statement to turn on error handling throughout the

program:

.LP

EXEC SQL WHENEVER sqlerror sqlprint;

.LP

EXEC SQL WHENEVER not found sqlprint;

.LP

PLEASE NOTE: this is *not* an exhaustive example of usage for

the EXEC SQL WHENEVER statement. Further examples of usage may

be found in SQL manuals (e.g., `The LAN TIMES Guide to SQL' by

Groff and Weinberg.)

.LP

Prior to version 2.1.0 the database name was single quoted:

.RS

EXEC SQL CONNECT 'test1';

.RE

.LP

As of version 2.1.0, the syntax has been simplified:

.LP

.RS

EXEC SQL CONNECT test1;

.RE

(The database name is no longer quoted.)

.LP

Specifying a server and port name in the connect statement is also possible

as of version 6.4. of PostgreSQL. The syntax is:

.LP

.RS

dbname[@server][:port]

.RE

.LP

or

.LP

.RS

<tcp|unix>:postgresql://server[:port][/dbname][?options]

.RE

.LP

.LP

EXEC SQL CREATE TABLE foo (number int4, ascii char(16));

.RS

EXEC SQL CREATE UNIQUE index num1 on foo(number);

.RE

EXEC SQL COMMIT;

.LP

.LP

EXEC SQL INSERT INTO foo (number, ascii)

.RS

VALUES (9999, 'doodad');

.RE

EXEC SQL COMMIT;

.LP

.LP

EXEC SQL DELETE FROM foo

.RS

WHERE number = 9999;

.RE

EXEC SQL COMMIT;

.LP

.LP

EXEC SQL SELECT foo INTO :FooBar FROM table1

.RS

WHERE ascii = 'doodad';

.RE

.LP

.LP

EXEC SQL DECLARE foo_bar CURSOR FOR

.RS

SELECT number, ascii FROM foo

.RS

ORDER BY ascii;

.RE

.RE

EXEC SQL FETCH foo_bar INTO :FooBar, DooDad;

.LP

...

EXEC SQL CLOSE foo_bar;

.RS

EXEC SQL COMMIT;

.RE

.LP

.LP

EXEC SQL UPDATE foo

.RS

SET ascii = 'foobar'

.RE

.RS

WHERE number = 9999;

.RE

EXEC SQL COMMIT;

.LP

.LP

The is no EXEC SQL PREPARE statement.

.LP

The complete structure definition MUST be listed

inside the declare section.

.LP

See the TODO file in the source for some more missing features.

.LP

.LP

ecpg returns 0 to the shell on successful completion, -1

for errors.

.LP

.PD0

.TP

.TP

.PD

.PD0

.TP

./ecpg/include.......source for\fIecpg\fP header files.

./ecpg/lib...........source for\fIecpg\fP libraries.

./ecpg/preproc.......source for\fIecpg\fP header files.

./ecpg/test..........source for\fIecpg\fP libraries.

(test contains examples of syntax for ecpg SQL-C.)

.PD

.TP

\fIPostgreSQL\fP binaries including\fIecpg\fP.

.PD

.TP

which are considered strings.

\fIPostgreSQL\fP headers including\fIecpglib.h\fP\fIecpgtype.h\fP

and\fIsqlca.h\fP.

.PD

.TP

.IR ecpg

returns 0 to the shell on successful completion, -1 for errors,

cc(1).

\fIPostgreSQL\fP libraries including\fIlibecpg.a\fP and

\fIlibecpg.so\fP.

Linus Tolke\fI<linus@epact.se>\fP

- original author of ECPG (up to version 0.2).

.br

.PP

Michael Meskes\fI<meskes@debian.org>\fP

- actual author and maintainer of ECPG.

.br

.PP

Thomas Good\fI<tomg@q8.nrnet.org>\fP

- author of this revision of the ecpg man page.

.br

.zZ