How to Dump and Restore PostgreSQL Database?

PostgreSQL remains among the most efficient and widely applied open-source relational database management systems. It provides the superior function of saving, configuring, and extracting information most effectively. In the process of migrating data, creating backups, or transferring databases between environments, knowing how to dump and restore PostgreSQL is essential.

In this article, we will go through the individual steps to dump and restore PostgreSQL databases using both the command-line interface (CLI) and pgAdmin, a popular graphical user interface for PostgreSQL management.

How to Dump a PostgreSQL Database?

A PostgreSQL dump file is a text file consisting of SQL statements that can recreate a database’s structure and content. This "backup" file can be used later to restore the database. Here, we will discuss two methods for dumping a PostgreSQL database: using the pg_dump command-line tool and pgAdmin.

Method 1: Using the pg_dump Command-Line Tool

The pg_dump command-line utility is the most commonly used method to dump a PostgreSQL database. It creates a logical backup, saving the database as a plain-text file or in a custom format.

Step 1: Open Terminal or Command Prompt

Start by opening the Terminal on Linux/Mac or Command Prompt on Windows.

Step 2. Navigate to PostgreSQL Bin Directory (Optional)

If the path to PostgreSQL's bin directory is not added to your system's PATH, a command 'cd' will be used to navigate to the directory. This directory is usually located within your PostgreSQL installation directory.

Step 3. Execute the pg_dump Command

The command for the pg_dump will be "pg_dump database_name". Optional parameters including username, hostname, and port settings can be specified here.

pg_dump -U username -h hostname -p port dbname > dump.sql

• Replace username with your PostgreSQL username.
  
• Replace hostname with the server where the database is located (use "localhost" if local).
  
• Replace port with the port number (default is 5432).
  
• Replace dbname with the name of the database we want to dump.
  
• Replace dump.sql with the name of your dump file.

Step 4. Enter Password (If Required)

Enter the password associated with the corresponding username when prompted.

Step 5. Verify Dump

After all the commands finish running, check that a file named 'dump.sql' (or any other name we want) has been created inside this directory. It will be in the current directory. The data file saves the SQL statements in order to set up the database structure and to insert the data.

Example:

pg_dump -U postgres -h localhost -p 5432 -d northwind > C:\Users\Sanket\Desktop\northwind_backup.sql

Output

Explanation:

Once we have completed these steps, we dump the Northwind database via the use of 'pg_dump' command line tool. Now the dump file is ready for restoring the database later or moving the database to another PostgreSQL instance.

Database administrators as well as developers perform dumping databases as a regular one-off operation to preserve the database data integrity and uptime in different scenarios.

Method 2: Using pgAdmin

For users who prefer a graphical interface, pgAdmin provides an easy way to create database backups.

Step 1: Open pgAdmin

Launch pgAdmin connect to your PostgreSQL server.

Step 2: Navigate to the Databases Section

In the object browser, click the + button to widen the server node, the Databases section under it.

Step 3: Right-click on the Database

Right-click on the database you want to dump and select "Backup."

Step 4: Specify Backup Options

A dialog box will appear, allowing you to select the backup type (plain, custom, tar) and specify the filename.

Step 5: Initiate Backup

Clicking on "Backup" to initiate the backup process. At the finishing point, you are left dump file that holds the database schema and data in it.

How to Restore a PostgreSQL Database?

PostgreSQL database recovery is one of the most important tasks in database administration. It can be used to recover from a backup, migrate data, or create a new environment. In this section, we will go over how to restore a PostgreSQL database. We will use the PostgreSQL command-line tool (psql) as well as the popular graphical interface (pgAdmin) to do this.

Method 1: Restoring Backup Using psql Command-Line Tool

The psql tool is commonly used to restore PostgreSQL backups from a SQL dump file.

Step 1: Open Terminal or Command Prompt

Open your terminal or command prompt window.

Step 2: Connect to PostgreSQL Server

Execute the following command to connect to the PostgreSQL server using the psql command-line tool:

psql -U postgres

Enter the password for the Postgres user if prompted.

Step 3: Create a New Database

Inside the psql environment, create a new database named 'recoverdb':

Step 4: Exit psql Environment

Type '\q' to exit the psql environment.

Step 5: Restore Backup

Outside the psql environment, use the following command to restore the backup file to the 'recoverdb' database:

psql -U postgres -d recoverdb -f "C:\Users\Sanket\Desktop\northwind_backup.sql"

Example:

Type the command to recover the dump file in recoverdb database which we created before.

Enter password and the database will be recovered from northwind_backup.sql dump file

Method 2: Restoring Backup Using pgAdmin

Restoring a database through pgAdmin is easy and user-friendly.

Step 1: Launch pgAdmin

Open pgAdmin and connect to your PostgreSQL server.

Step 2: Create a New Database

Navigate to the Databases section, right-click on the server, and select "Create" > "Database...". Enter recoverdb as the database name and click "Save".

Step 3: Restore Backup

Right-click on the 'recoverdb' database you just created and select "Restore." In the dialog box that appears, navigate to the location of your backup file ('northwind_backup.sql') and select it.

Click "Restore" to initiate the restoration process.

Conclusion

Backup/Restore and database dumping are common tasks for database administrators and developers. Whether you are migrating data, making backups, or transferring databases between environments, understanding how to dump and restore PostgreSQL databases is crucial.

By following the steps outlined in this article, we can reliably and efficiently dump and restore our PostgreSQL databases without risking data integrity or availability. Both pg_dump and pgAdmin offer powerful options for ensuring our database backups are properly created and restored.