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Data Manipulation Language DML

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In this video, we will understand.

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Define what data manipulation language DML is and explain its purpose in managing data.

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Identify and apply the main DML commands, insert, update, and delete.

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Recognize the importance of data integrity and safe data handling using transactions.

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What is data manipulation language?

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Data manipulation language, or DML, is a part of SQL that helps us work with the data stored in tables.

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It allows us to add, change, or remove information without changing the table structure.

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The main DML commands are insert, update, and delete.

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Think of DML like managing a library catalog.

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You can add new books, update their information, or remove old books that are no longer available.

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Types of DML commands

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First up is insert. The insert command is how we introduce new records or rows into a table.

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Think of it as adding a new user.

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It helps your database grow with fresh information.

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For example, the insert command adds new entries to a table.

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Here we add three employees, John Doe, Jane Smith, and Sam Green, with their salaries.

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After running select star from employees, all three records appear in the database.

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It's like adding new team members to your company records.

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Next is the update command.

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This is vital for making corrections or improvements to data that is already in your table.

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Here, we're updating John Doe's salary to 5,500 using his employee ID 101.

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Next, we update Jane Smith's record.

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Changing her salary to 8,000 and shortening her name to Jane S.

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With the WHERE clause, only those specific records are modified, keeping all other data safe.

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Finally, we have the DELETE command.

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This is used to remove records that are no longer needed.

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In this example, we're deleting the employee with ID 103 from the employee's table.

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By using the WHERE clause, we make sure only that specific employee's record is deleted.

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Nothing else is affected.

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This keeps the database organized and free of outdated information.

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Ensuring data integrity.

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To keep data safe and correct, we use constraints in foreign keys.

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They make sure information stays consistent.

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For example, no two employees can have the same ID.

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A transaction is a group of SQL actions that work together.

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Transactions have three main steps.

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Begin, starts, the operation.

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Commit, saves the changes, and roll back, cancels them if something goes wrong.

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Either all changes happen or none do.

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This ensures that our data always stays reliable.

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Data manipulation language lets us safely add, update, or remove data.

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Understanding DML helps us manage information effectively

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and is the foundation of every database system.