PostgreSQL Database Commands Tutorial

This guide outlines common PostgreSQL commands to connect to a database, list tables, describe table structures, query data, and update data.

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1. Connect to the Database

Use the following command to connect to the database:

psql -h postgres -U user -d db_name -p 5432

After executing the command, you’ll be prompted for the password:

your_secure_password

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2. List Tables in the Database

Once connected, list all tables with:

\dt;

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3. Describe the Tables

To view the structure of specific tables, use the \d command:

\d users;

\d settings;

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4. Check Values in a Table

To view all rows from the table_name table, execute:

SELECT * FROM table_name;

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5. Check Table Structure

To see the structure of the table_name table, use:

\d table_name

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6. (Optional) Filter Rows where reminder_sent is true

To view only the rows in the subscriptions table where reminder_sent is true, run:

SELECT * FROM subscriptions WHERE reminder_sent = true;

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7. Reset All reminder_sent Values to false

To update the reminder_sent column and set all values to false, run:

UPDATE subscriptions SET reminder_sent = false;

After updating, you can verify the changes with:

SELECT reminder_sent FROM subscriptions;

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This guide provides a quick reference for some useful PostgreSQL commands. For more detailed information, refer to the official PostgreSQL documentation.