mirror of https://github.com/postgres/postgres
Bruce Momjian
27 years ago
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4c71609c1c
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.\" This is -*-nroff-*- |
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.\" XXX standard disclaimer belongs here.... |
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.TH ECPG UNIX 2/11/98 PostgreSQL PostgreSQL |
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.TH ECPG UNIX 11/28/98 PostgreSQL \fIPostgreSQL\fP |
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.SH NAME |
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ecpg - embedded SQL preprocessor for C |
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ecpg - embedded SQL preprocessor for C / PostgreSQL |
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.SH SYNOPSIS |
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.BR ecpg |
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[\c |
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.BR "-v" |
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] |
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[\c |
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.BR "-d" |
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] |
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[\c |
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.BR "-o" |
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outfile |
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] |
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file1 |
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[file2] |
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[...] |
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.in -5n |
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.\" \fBecpg\fR [-v ] [-t] [-I include-path ] [-o outfile ] file1 [ file2 ] [ ... ] |
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\fBecpg\fR [-v ] [-t] [-I include-path ] [-o outfile ] file1 [ file2 ] [ ... ] |
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.SH DESCRIPTION |
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ecpg an embedded SQL in C package for PostgreSQL. It enables you to |
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develop C programs with embedded SQL code. |
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.B \fIecpg\fP |
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is an embedded SQL preprocessor for C / PostgreSQL. It |
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enables development of C programs with embedded SQL code. |
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.PP |
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.IR "ecpg" |
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understands the following command-line options: |
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.B \fIecpg\fP |
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is ultimately intended to be as compliant as possible with the |
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ANSI SQL-2 standard and existing commercial ESQL/C packages. |
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.SH OPTIONS |
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.B \fIecpg\fP |
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interprets the following flags when it is invoked |
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on the command line: |
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.PP |
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.PD 0 |
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.TP 10 |
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.BI \-v |
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Print version information. |
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.PD |
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.TP |
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.BR "-v" |
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Print version information. |
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.B \-t |
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Turn off auto-transactin mode. |
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.PD |
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.TP |
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.BR "-d" |
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Turn on debugging. |
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.PD |
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.TP |
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.BR "-o" " outfile" |
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Specifies that |
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.IR "ecpg" |
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should write all its output to |
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.IR "outfile". If no such option is given the output is written to foo.c |
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if the input file was name foo.pgc or to foo.bar.c if the input file was |
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foo.bar. |
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.B \-I include-path |
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Specify additional include path. Defaults are \., |
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/usr/local/include, the PostgreSQL include path which is defined at compile |
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time (default: /usr/local/pgsql/lib), /usr/include |
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.PD |
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.TP |
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.BR "file1, file2, ..." |
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The files to be processed. |
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.SH "BUGS" |
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The return code is alway -1 in case of an error. You cannot see which error |
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occured by examining the return code. |
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.B \-o |
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Specifies that ecpg should write all its output to outfile. |
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If no such option is given the output is written to foo.c |
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(if the input file was named foo.pgc.) |
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If the input file was named foo.bar the output file will be |
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named foo.bar.c. |
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.PD |
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.TP |
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The cursor is opened when the declare statement is issued. |
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.B file1, file2... |
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The files to be processed. |
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.\" |
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.SH INSTALLATION |
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The |
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.B \fIecpg\fP |
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preprocessor is built during the PostgreSQL installation. Binaries and |
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libraries are installed into the PGBASE (i.e., /usr/local/pgsql/... ) |
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subdirectories. |
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.SH PREPROCESSING FOR COMPILATION |
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.B \fIecpg\fP |
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.\" (-d ) (-o file) file.pgc ( 2> ecpf.log) |
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(-o file) file.pgc |
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.LP |
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.\" The optional \-d flag turns on debugging and 2> ecpg.log |
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.\" redirects the debug output. The .pgc extension is an |
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.\" arbitrary means of denoting ecpg source. |
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The .pgc extension is an arbitrary means of denoting ecpg source. |
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.SH COMPILING AND LINKING |
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Assuming the \fIPostgreSQL\fP binaries are in /usr/local/pgsql: |
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.LP |
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gcc -g -i /usr/local/pgsql/include (-o file) file.c |
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-L /usr/local/pgsql/lib -lecpg -lpq |
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.SH ECPG GRAMMAR |
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.LP |
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.SH LIBRARIES |
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.LP |
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The preprocessor will prepend two directives to the source: |
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.LP |
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\fI#include <ecpgtype.h>\fP and \fI#include <ecpglib.h>\fP |
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.SH VARIABLE DECLARATION |
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Variables declared within ecpg source code must be prepended with: |
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.LP |
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EXEC SQL BEGIN DECLARE SECTION; |
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.LP |
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Similarly, variable declaration sections must terminate with: |
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.LP |
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EXEC SQL END DECLARE SECTION; |
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.LP |
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NOTE: prior to version 2.1.0, each variable had to be declared |
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on a separate line. As of version 2.1.0 multiple variables may |
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be declared on a single line: |
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.LP |
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char foo(16), bar(16); |
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.LP |
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.SH ERROR HANDLING |
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The SQL communication area is defined with: |
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.LP |
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EXEC SQL INCLUDE sqlca; |
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.LP |
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NOTE: the lowercase `sqlca'. While SQL convention may be |
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followed, i.e., using uppercase to separate embedded SQL |
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from C statements, sqlca (which includes the sqlca.h |
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header file) MUST be lowercase. This is because the EXEC SQL |
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prefix indicates that this INCLUDE will be parsed by ecpg. |
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ecpg observes case sensitivity (SQLCA.h will not be found.) |
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EXEC SQL INCLUDE can be used to include other header files |
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as long as case sensitivity is observed. |
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.LP |
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The sqlprint command is used with the EXEC SQL WHENEVER |
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statement to turn on error handling throughout the |
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program: |
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.LP |
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EXEC SQL WHENEVER sqlerror sqlprint; |
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.LP |
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EXEC SQL WHENEVER not found sqlprint; |
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.LP |
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PLEASE NOTE: this is *not* an exhaustive example of usage for |
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the EXEC SQL WHENEVER statement. Further examples of usage may |
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be found in SQL manuals (e.g., `The LAN TIMES Guide to SQL' by |
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Groff and Weinberg.) |
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.LP |
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.SH CONNECTING TO THE DATABASE SERVER |
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Prior to version 2.1.0 the database name was single quoted: |
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.RS |
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EXEC SQL CONNECT 'test1'; |
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.RE |
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.LP |
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As of version 2.1.0, the syntax has been simplified: |
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.LP |
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.RS |
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EXEC SQL CONNECT test1; |
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.RE |
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(The database name is no longer quoted.) |
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.LP |
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Specifying a server and port name in the connect statement is also possible |
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as of version 6.4. of PostgreSQL. The syntax is: |
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.LP |
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.RS |
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dbname[@server][:port] |
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.RE |
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.LP |
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or |
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.LP |
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.RS |
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<tcp|unix>:postgresql://server[:port][/dbname][?options] |
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.RE |
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.SH QUERIES |
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.LP |
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.SS Create Table: |
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.LP |
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EXEC SQL CREATE TABLE foo (number int4, ascii char(16)); |
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.RS |
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EXEC SQL CREATE UNIQUE index num1 on foo(number); |
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.RE |
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EXEC SQL COMMIT; |
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.LP |
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.SS Insert: |
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.LP |
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EXEC SQL INSERT INTO foo (number, ascii) |
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.RS |
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VALUES (9999, 'doodad'); |
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.RE |
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EXEC SQL COMMIT; |
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.LP |
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.SS Delete: |
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.LP |
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EXEC SQL DELETE FROM foo |
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.RS |
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WHERE number = 9999; |
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.RE |
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EXEC SQL COMMIT; |
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.LP |
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.SS Singleton Select: |
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.LP |
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EXEC SQL SELECT foo INTO :FooBar FROM table1 |
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.RS |
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WHERE ascii = 'doodad'; |
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.RE |
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.LP |
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.SS Select using Cursors: |
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.LP |
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EXEC SQL DECLARE foo_bar CURSOR FOR |
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.RS |
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SELECT number, ascii FROM foo |
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.RS |
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ORDER BY ascii; |
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.RE |
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.RE |
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EXEC SQL FETCH foo_bar INTO :FooBar, DooDad; |
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.LP |
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... |
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EXEC SQL CLOSE foo_bar; |
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.RS |
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EXEC SQL COMMIT; |
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.RE |
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.LP |
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.SS Updates |
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.LP |
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EXEC SQL UPDATE foo |
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.RS |
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SET ascii = 'foobar' |
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.RE |
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.RS |
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WHERE number = 9999; |
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.RE |
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EXEC SQL COMMIT; |
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.LP |
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.SH BUGS |
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.LP |
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The is no EXEC SQL PREPARE statement. |
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.LP |
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The complete structure definition MUST be listed |
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inside the declare section. |
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.LP |
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See the TODO file in the source for some more missing features. |
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.LP |
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.SH "RETURN VALUE" |
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.LP |
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ecpg returns 0 to the shell on successful completion, -1 |
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for errors. |
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.LP |
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.SH "SEE ALSO" |
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.PD 0 |
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.TP |
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ecpg does not understand enum datatypes. |
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\fIcc\fP(1), \fIpgintro\fP(l), \fIcommit\fP(l), \fIdelete\fP(l) |
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.TP |
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The is no exec sql prepare statement. |
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\fIfetch\fP(l), \fIselect\fP(l), \fIsql\fP(l) , \fIupdate\fP(l) |
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.PD |
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.SH FILES |
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.PD 0 |
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.TP |
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The complete structure definition has to be listed inside the declare section for ecpg to be able to understand it. |
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.B /usr/src/pgsql/postgresql-${ver}/src/interfaces... |
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./ecpg/include.......source for \fIecpg\fP header files. |
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./ecpg/lib...........source for \fIecpg\fP libraries. |
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./ecpg/preproc.......source for \fIecpg\fP header files. |
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./ecpg/test..........source for \fIecpg\fP libraries. |
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(test contains examples of syntax for ecpg SQL-C.) |
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.PD |
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.TP |
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Each variable has to be defined on a line on its own. |
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.B /usr/local/pgsql/bin |
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\fIPostgreSQL\fP binaries including \fIecpg\fP. |
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.PD |
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.TP |
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There is no way yet to fill a complete array with one call except arrays of [unsigned] char |
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which are considered strings. |
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.B /usr/local/pgsql/include |
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\fIPostgreSQL\fP headers including \fIecpglib.h\fP \fIecpgtype.h\fP |
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and \fIsqlca.h\fP. |
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.PD |
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.TP |
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ecpg cannot use pointer variables except [unsigned] char * |
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.SH "RETURN VALUE" |
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.IR ecpg |
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returns 0 to the shell on successful completion, -1 for errors, |
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.SH "SEE ALSO" |
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cc(1). |
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.B /usr/local/pgsql/lib |
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\fIPostgreSQL\fP libraries including \fIlibecpg.a\fP and |
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\fIlibecpg.so\fP. |
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.SH AUTHORS |
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Linus Tolke \fI<linus@epact.se>\fP |
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- original author of ECPG (up to version 0.2). |
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.br |
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.PP |
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Michael Meskes \fI<meskes@debian.org>\fP |
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- actual author and maintainer of ECPG. |
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.br |
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.PP |
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Thomas Good \fI<tomg@q8.nrnet.org>\fP |
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- author of this revision of the ecpg man page. |
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.br |
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.zZ |
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