Postgres_multiple_databases

Postgres Multiple Databases

PostgreSQL provides the ability to create and manage multiple databases within a single PostgreSQL server instance. Each database is completely independent and can have its own set of tables, views, functions, and other database objects.

Creating a New Database

To create a new database in PostgreSQL, you can use the following SQL command:

CREATE DATABASE database_name;

For example, to create a database named “mydatabase”, you can execute:

CREATE DATABASE mydatabase;

Connecting to a Database

To connect to a specific database in PostgreSQL, you need to specify the database name in the connection string. Here’s an example of a connection string:

postgres://username:password@localhost:5432/database_name

In the above connection string, “username” and “password” are the credentials for the PostgreSQL user, “localhost” is the host where the PostgreSQL server is running, “5432” is the default port for PostgreSQL, and “database_name” is the name of the database you want to connect to.

Switching between Databases

Once you are connected to a PostgreSQL server, you can switch between different databases using the following command:

\c database_name

For example, to switch to the “mydatabase” database, you can execute:

\c mydatabase

Dropping a Database

To delete a database in PostgreSQL, you can use the following SQL command:

DROP DATABASE database_name;

Keep in mind that dropping a database will permanently delete all the data and database objects within it, so use this command with caution.

Example

Let’s say you have created two databases named “db1” and “db2”. To switch between them, you can use the following steps:

• Create the databases:

CREATE DATABASE db1;
CREATE DATABASE db2;

• Connect to “db1” using the connection string:

postgres://username:password@localhost:5432/db1

• Switch to “db2” using the PostgreSQL command:

\c db2

By following these steps, you can effectively work with multiple databases in PostgreSQL.