However, most system catalogs are database-specific.Įach system catalog name starts with “pg_”. So you shouldn’t change the system catalogs unless you really know what you’re doing.Ī few system catalogs are shared across all databases in the PostgreSQL cluster. You can insert new rows, update values, add columns – or potentially mess up your system. These catalogs are regular tables where you can manipulate data as you do with other tables. System catalogs are where a database management system stores schema metadata, such as information about databases, tables, and columns. Each catalog is a collection of schemas, and each schema has a set of tables. When you set up PostgreSQL in your machine, you spin up a PostgreSQL cluster, a server that hosts databases. This tutorial aims to give you insights into how PostgreSQL system catalogs can help you manage your schemas, databases, tables, and even table columns. ![]() In this tutorial, you’ll learn about the internal building blocks of PostgreSQL – also known as system catalogs – to see how the PostgreSQL backend is structured. You can view EDUCBA’s recommended articles for more information.PostgreSQL is a well-known database engine that allows you to write performant SQL queries. We hope that this EDUCBA information on “PostgreSQL Show Tables” was beneficial to you. We can show all the tables of a particular database in PostgreSQL using either of the three ways that include the metacommands of the psql utility, using the pg_tables table of pg_catalog, and using the tables table of information_schema. We can observe that three records are retrieved instead of two as this query retrieves the views along with tables, and remote_educba_data is the view in the educba database. We can use the following query statement using the following query as that tables table inside the information_schema stores the details of the tables of the database. There is one more way to retrieve the list of the tables of the particular database. Finally, we can execute the following query to show the tables in PostgreSQL.įrom the above query, we can observe the details about whether the tables have the indexes on them, rules, triggers, and security associated with it. Hence, we will need to retrieve the records of the pg_tables table except for the records whose schema names are information_schema and pg_catalog. The system tables, also called schemas named information_schema and pg_catalog, are already present in our PostgreSQL once installed. We can also make use of the alternative PostgreSQL query on the table pg_tables, which is located inside the pg_catalog database that stores the details of all the tables that include all the user-defined tables and the system tables present in the PostgreSQL database. Using the pg_tables to Get the List of Tables We can observe that besides the name of the table, its owner, and schema type, we can get the size of the table and the additional description if set against the table. To get the additional details about the retrieved tables, we can use the same meta-command and append the + plus operator to it, as shown below. We can observe that two tables, namely demo and educba_demo, are present in the Postgres database and are public. Now, to show all the tables stored inside the educba database, we can use meta-command \dt. We will use the metacommand \c as shown below to connect to the educba database. We can use the alternative command named \connect that helps us connect to the database. ![]() Now, we will connect to the educba database using the meta-command \c and the name of the database. We can use a meta-command named \d, as shown below, to get the database names list. For example, here, the user is Postgres, whose password is “a”.įurther, after connecting to the database server, we will need to list all the available databases in the database server so that we can choose the one and connect to it and retrieve the tables of that database. The execution of the above command statement gives an output, as shown below, which demands the password as soon as the command is fired, and we need to mention the password set against the user using which we are trying to login. ![]() We will first need to login to our PostgreSQL database server through the terminal using the following command where Postgres is the user name using which I will log in to my Postgres database server, and W is to mention I will enter that password after the execution of the following command.
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