dropdb Command in Linux

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The Linux dropdb command removes the existing PostgreSQL database. To use this command the user must be the superuser or owner of the database. Note that the dropdb command is a wrapper for the SQL DROP DATABASE query. Unlike the SQL query, it can be executed directly from the terminal without entering the PostgreSQL interactive session. Use this command cautiously, as it permanently deletes the database and its data.

Table of Contents

Here is a comprehensive guide to the options available with the dropdb command −

• Prerequisites of using the dropdb Command
• Syntax for dropdb Command
• dropdb Command Options
• Listing PostgreSQL Databases
• Examples of dropdb Command in Linux

Prerequisites of using the dropdb Command

To use the dropdb command, PostgreSQL must be installed and configured in Linux. To install PostgreSQL in Linux, use the following commands −

To install PostgreSQL on Ubuntu, Debian, and Debian-based distributions, use −

sudo apt install postgresql postgresql-contrib

To get it on Fedora, use −

sudo dnf install postgresql postgresql-server

After installation, start the PostgreSQL service.

To verify the installation, check the version −

psql --version

Syntax for dropdb Command

The general syntax of using the dropdb command on Linux is as follows −

dropdb [options] [database]

The dropdb command accepts various [options], such as making output interactive, printing command version, and displaying help. While the [database] field is used to specify the database name.

dropdb Command Options

Options used with the dropdb command are listed below −

Listing PostgreSQL Databases

To delete a database, first list the existing PostgreSQL databases. To list databases, log in as database admin −

sudo -u postgres psql postgres

Here the psql command runs as the postgres user, connecting to the postgres database. An interactive terminal-based front end will be enabled.

To list the database, use the following command −

\list

The \l command can also be used in place of \list.

Note − To exit the Postgres interactive session, use \q.

Examples of dropdb Command in Linux

This section explains the usage of the dropdb command in Linux with examples −

• Delete the Database
• Delete a Database from a Specific Server
• Delete Database Interactively
• Display a Notice if the Database does not Exist

Delete the Database

To delete the database from the default database server, use the dropdb command with the database name.

dropdb mydatabase

To display the SQL commands that dropdb sends to the server, use the -e or --echo option.

dropdb -e mydatabase

Delete a Database from a Specific Server

To delete a database from a server on a specific host and port, use −

dropdb -h myhost -p 4302 -e mydatabase

Here, -h and -p flags are used to specify the hostname and port number respectively.

Delete Database Interactively

To delete the database interactively, use the -i option. It displays a prompt before deleting the database.

dropdb -i -e mydatabase

Display a Notice if the Database does not Exist

To print a notice if the database does not exist, use the --if-exist option −

dropdb --if-exists mydatabase

Conclusion

The dropdb command on Linux deletes the PostgreSQL database. It can be used to delete the database from a specific server as well. It is a useful tool for quickly removing databases.

This tutorial covered the prerequisites of using the dropdb command, its syntax, options, and usage through various examples.