Database Operations - Overview

Databases Postgres
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In this article, we will explore the key database operations that we typically perform on a regular basis. These operations are broadly categorized into Data Definition Language (DDL), Data Manipulation Language (DML), and Data Query Language (DQL). Additionally, we will touch upon Transaction Control Language (TCL) commands like COMMIT and ROLLBACK.

Key Concepts Explanation

DDL - Data Definition Language

DDL commands are used to define, modify, and drop database objects. Some common DDL commands include:

CREATE TABLE table_name (
    column1 datatype,
    column2 datatype,
    ...
);

ALTER TABLE table_name
ADD column_name datatype;

DROP TABLE table_name;

DML - Data Manipulation Language

DML commands are used to manipulate data within the database tables. Some common DML commands include:

INSERT INTO table_name (column1, column2, ...)
VALUES (value1, value2, ...);

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UPDATE table_name
SET column1 = value1,
    column2 = value2
WHERE condition;

DELETE FROM table_name
WHERE condition;

DQL - Data Query Language

DQL commands are used to retrieve data from the database tables. The most common DQL command is:

SELECT column1, column2, ...
FROM table_name
WHERE condition;

Hands-On Tasks

Now, let’s practice some hands-on tasks to solidify our understanding:

  1. Create a new table with appropriate columns using DDL commands.
  2. Insert some sample data into the table using DML commands.
  3. Write a SQL query to retrieve specific information from the table using DQL commands.

Conclusion

In conclusion, understanding and mastering database operations such as DDL, DML, and DQL are essential for effectively managing and querying data in a database. Practice these concepts regularly and engage with the community for further learning.