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/** -*-C-*-ish
Kaya standard library
Copyright (C) 2004, 2005 Edwin Brady
This file is distributed under the terms of the GNU Lesser General
Public Licence. See COPYING for licence.
*/
"<summary>PostgreSQL database interface module</summary>
<prose>This module allows querying of <link url='http://www.postgresql.org'>PostgreSQL</link> databases, using the standard <moduleref>DB</moduleref> API.</prose>"
module PostgresDB;
import Builtins;
// Postgres API suitable for use with the DB module.
import Prelude;
import public DB;
%include "pg_inter.h";
%imported "pg_inter";
%link "pq";
"<summary>A PostgreSQL database connection</summary>
<prose>This data type holds information about a database connection.
The type <code>PGDB</code> is a type synonym for <code>DB::DBHandle<PGConnection></code></prose>
<related><moduleref>DB</moduleref></related>"
abstract data PGConnection = PGCon(Ptr cdata);
type PGDB = DBHandle<PGConnection>;
foreign "pg_inter.o" {
Ptr pg_connect(String info) = pg_connect;
Bool pg_ok(Ptr p) = pg_ok;
Ptr pg_exec(Ptr vm, Ptr cdata, String query, a errstr) = pg_exec;
[[DBValue]] pg_getstrs(Ptr pr) = pg_getstrs;
Int pg_numrows(Ptr pr) = pg_numrows;
Int pg_numcols(Ptr pr) = pg_numcols;
[String] pg_colnames(Ptr pr) = pg_colnames;
String pg_getError(Ptr pgc) = pg_getError;
Void pg_close(Ptr cdata) = pg_close;
Ptr do_pgprepare(String query) = do_pg_prepare;
Ptr pg_execp(Ptr vm, Ptr cdata, Ptr query, a errstr, [Maybe<String>] params) = pg_execp;
}
"<argument>The String contains a description of the error</argument>
<summary>Connection error</summary>
<prose>This Exception is thrown if the connection failed.</prose>"
Exception CantConnect(String err);
"<argument>The String contains a description of the error</argument>
<summary>Query error</summary>
<prose>This Exception is thrown if a query failed.</prose>"
Exception ExecError(String err);
"<summary>Column out of range.</summary>
<prose>This Exception should never occur. It is thrown if an attempt is made to read a column that doesn't exist.</prose>"
Exception ColumnOutOfRange();
"<argument name='info'>The database host to connect to. The syntax for this argument is described in <link url='http://www.postgresql.org/docs/8.2/static/libpq-connect.html'>the Postgres documentation</link>.</argument>
<summary>Connect to a database.</summary>
<prose>Use this function to connect to the database. You can then use the functions from <moduleref>DB</moduleref> to query the database.</prose>
<example>conninfo = \"dbname='mysite' user='web' password='WHSpWXPPh5'\";
db = PostgresDB::connect(conninfo);
res = exec(db,\"SELECT * FROM pagedata WHERE page_id = 10\");</example>
<related><moduleref>DB</moduleref></related>"
public DBHandle<PGConnection> connect(String info)
{
pgc = pg_connect(info);
if (pg_ok(pgc)==false) {
throw(CantConnect(pg_getError(pgc)));
}
con = PGCon(pgc);
return(DBh(con,
exec_pg, defaultIncExec,
prepare_pg, execp_pg, defaultIncExecPrepared,
defaultGetRow, defaultIncDiscard, close_pg));
}
DBStatement<PGConnection> prepare_pg(PGDB con, String query) {
return DBStatement(con,do_pgprepare(query));
}
DBResult execp_pg(DBStatement<PGConnection> prep, [Maybe<String>] params) {
err = "Unknown error";
pr = pg_execp(getVM(),prep.con.handle.cdata, prep.statement, err, params);
if (null(pr)) {
throw(ExecError(err));
}
strs = pg_getstrs(pr);
rows = pg_numrows(pr);
cols = pg_numcols(pr);
colnames = pg_colnames(pr);
return DBRes(strs,rows,cols,colnames,pr);
}
"Execute a query on the given connection."
DBResult exec_pg(PGConnection con, String query)
{
err = "Unknown error";
pr = pg_exec(getVM(),con.cdata, query, err);
if (null(pr)) {
throw(ExecError(err));
}
strs = pg_getstrs(pr);
rows = pg_numrows(pr);
cols = pg_numcols(pr);
colnames = pg_colnames(pr);
return DBRes(strs,rows,cols,colnames,pr);
}
"Close a connection to the database."
Void close_pg(PGConnection con)
{
pg_close(con.cdata);
}
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