If this is the case on your system, you will need to check the Connect as same Unix user? box on the form. Sometimes PostgreSQL is set up to authenticate users by their Unix username, rather than by a separate login and password (the ident authentication mode). Logging in as some other less privileges user may work at first, but you will not be able to use all of the features of the module. You must enter valid login details for your database server, typically for the postgres user who has full access to all databases and features. If PostgreSQL is running by Webmin does not know the administration username and password needed to connect to it, and *PostgreSQL Login* form will be displayed on the main page. On most Linux distributions, the PostgreSQL packages include a bootup action script called postgres or postgresql that is not enabled by default. If you want it to be started at boot time from now on, use the Bootup and Shutdown module (covered on Bootup and Shutdown) to create a new action to start it. Just click the Start PostgreSQL Server button at the bottom of the page. If the message PostgreSQL is not running on your system appears, you will need to start the database server before this module can be used to manage it. The most common ones are covered in the next few paragraphs. Instead, some kind of error message will be displayed. If Webmin detects that PostgreSQL is not installed, have not been initialised or cannot be connected to, the main page will not appear as shown in the image above. When you click on its icon in the Servers category of Webmin, the main page displays a list of existing databases on your system as shown in this screenshot: In many ways it is very similar to the MySQL Database Server module. This module allows an administration to manage databases, tables, fields and records in a PostgreSQL server. This is the only file that Webmin edits directly - all other database configuration is done by connecting to the database server, either directly or through the psql command. The most important is pg_hba.conf, which lists client hosts that are allowed to connect to the server. As well, there are several text configuration files that effect the operation of the server and clients. None of the clients access the database files directly - that is left entirely to the server.Īll of the PostgreSQL database files are stored under a directory such as /var/lib/pgsql or /usr/local/pgsql. The most commonly used is the psql command, which allows a user to execute SQL queries and view the results. PostgreSQL consists of a server process that reads and writes the actual database files, and a set of client programs that communicate with the server. Its operation is the same on all operating systems, and thus so is the Webmin module for managing it. Packages for PostgreSQL come with many Linux distributions, and it can be compiled and installed on almost all varieties of Unix. Its syntax is not covered in this chapter though. Almost all databases use SQL, and its syntax is generally the same across all the different database packages, such as Oracle, PostgreSQL and MySQL. SQL (which stands for Structured Query Language) is a language for extracting data from or updating data in a database. Some fields can also contain multiple values, like an array. Fields can be thought of as the columns in a table, and the actual records of data as the rows. Tables contain records, each of which usually contains information about some object, such as a person, product or purchase. A table in turn contains fields, each of which has a type and size. Popular languages like Perl, C, Java and PHP all have APIs for accessing a PostgreSQL database.Ī PostgreSQL server can host multiple databases, and each database can contain multiple tables. It is most useful for programmers writing applications that need to use a database to store information. Like the MySQL Database Server, PostgreSQL is a free database server that supports multiple databases and tables, and allows clients to query them with SQL. 17 Configuring the PostgreSQL Database Server module.2 The PostgreSQL Database Server module.
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