How to select a database in Postgres with PHP?

Question

I have the following string connection:

$string_connection = "host=localhost port=5432 user=postgres password=postgres";
$conn = pg_connect($string_connection );

Later in my code, I need to select a database:

pg_connect("dbname=my_database");

But, always I have the following error:

Warning: pg_connect(): Unable to connect to PostgreSQL server: fe_sendauth: no password supplied in ..\class.databases.php on line 142

But, in the example of PHP.net, they do this. Another example:

pg_query($conn,'\connect my_database');

Why this dont work?

When I do a backup with PgAdmin, I got the following strings:

SET statement_timeout = 0;
SET client_encoding = 'UTF8';
SET standard_conforming_strings = off;
SET check_function_bodies = false;
SET client_min_messages = warning;
SET escape_string_warning = off;

DROP DATABASE my_database;

CREATE DATABASE my_database WITH ENCODING = 'UTF8' LC_COLLATE = 'Portuguese_Brazil.1252' LC_CTYPE = 'Portuguese_Brazil.1252';

ALTER DATABASE my_database OWNER TO postgres;

\connect my_database

Whe I try to run this script with pg_query, I have erros:

Warning: pg_query(): Query failed: ERRO: syntax error in "\" LINE 1: \connect my_database ^

I need to select a dabatase to create a schema then create my tables... I dont know how to do this with Postgres.

Why not select the database when you initially run pg_connect? — andrewsi
– andrewsi, Commented Jul 17, 2013 at 17:56
Because the user will select or create a database, where it can create a schema and then run a set of queries / sql script. — Marcelo Rodovalho
– Marcelo Rodovalho, Commented Jul 17, 2013 at 18:01
In that case, you're going to have to pass all the parameters in on the second pg_connect call, I think. I assume the examples on php.net are for databases that don't require passwords for a connection. — andrewsi
– andrewsi, Commented Jul 17, 2013 at 18:04
Yeah, I think too. But what about the pg_query($conn,'\connect my_database'); ? — Marcelo Rodovalho
– Marcelo Rodovalho, Commented Jul 17, 2013 at 18:05
Where did you see that code? I can't find it on the php.net pages for pg_connect or pg_query. — andrewsi
– andrewsi, Commented Jul 17, 2013 at 18:07

Oliver · Accepted Answer · 2013-07-17 18:00:17Z

2

Add "dbname=my_database" to your connection string to select a database at conection time.

answered Jul 17, 2013 at 18:00

Oliver

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1 Comment

Marcelo Rodovalho Over a year ago

Yeah, I know, but if need to change the database after? I need to close and re-connect?

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