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In this video, we will understand what data definition language DDL means in SQL.

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Use basic DDL commands like create, alter, and drop to manage database tables.

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Apply best practices for naming, data types, and table design.

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What is DDL?

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Data definition language or DDL is a part of SQL used to define and manage the structure of a database.

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It helps you create, modify, or delete tables and columns, the building blocks that store data.

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Instead of changing data inside tables, DDL focuses on how those tables are designed and organized.

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Creating tables

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The create table command is used to make a new table in a database.

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Each table has columns with data types such as integer for whole numbers.

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Text for words or names, real for decimal values.

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For example, you can create a table named customer with columns like name, age, email, and city.

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Each column stores a specific type of information, modifying and deleting tables.

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When your database changes, you can update its structure using the alter table command.

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This lets you add new columns, rename existing ones, or even change data types if needed.

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If a table is no longer useful, the drop table command can remove it permanently,

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but use it carefully because once dropped, all its data is lost.

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Best practices and summary

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While designing tables, always use clear, meaningful names.

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Choose proper data types for accuracy.

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Check for errors like table already exists or no such table.

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Data definition language helps you build and organize the structure of a database.

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By mastering commands like create, alter, and drop,

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you can design databases that are well structured, accurate, and easy to maintain.