Structured Query Language is used to develop, modify and remove database and database objects in a database management system. It also helps restore, retrieve and update the data in a database. SQL is an ordinary language for developing, obtaining, and exploiting database management systems. SQL works for all present relational database management systems, like SQL Server, Oracle, MySQL, etc. Many SQL Training Institute in Noida is providing complete knowledge about this particular course.
Different types of SQL Commands
Data Definition Language-: We use DDL commands for creating and altering the database. We can also use it as a database object in the relational database management system. With the help of DDL, we can also work, like CREATE DATABASE, CREATE TABLE, ALTER TABLE, etc. The most useful DDL commands are CREATE, DROP, ALTER, and TRUNCATE.
- CREATE-: This command is useful to develop a database and database object like a table, index, opinion, motivation, stored process, etc.
- ALTER-: Alter command is useful in restructuring the database object and the settings in the database.
- TRUNCATE-: The truncate command helps to delete all data from the table. This command can empty a table.
- DROP-: We can apply this command to extract data from a database.
Data Manipulation Language-: DML commands are mainly used for manipulating data in a relational database management system. We can also use it for counting, removing, modifying data in the database system, like INSERT INTO TableName, DELETE FROM TableName, UPDATE tableName set data, etc. The most beneficial DML commands are Insert Into, Delete From, and UPDATE.
- INSERT INTO-: It is useful in adding details to the database table.
- UPDATE-: We can use this command as updating data in a database table. If we have to add any condition then we can use the WHERE clause to update a specific row.
- DELETE-: We can apply this command to delete the details from the database. If we have any condition we can use the WHERE clause to delete the specific row which meets the condition.
More Useful Types of SQL Commands
Data Query Language-: DQL command is useful for fetching details. It is also useful for selecting details from the table, view, temp table, table variable, etc. There is only one command under DQL i.e., Select command.
Data Control Language-: DCL Command is useful for delivering and taking back the access liberties on the database and database entities. We can apply the DCL command for controlling users’ access to the data. DCL has two commands Revoke and Grant.
- GRANT-: Grant is useful in providing access rights to users.
- REVOKE-: It helps to take back the permit request from the user, it cancels the permit request of the user from the database object.
Transaction Control Language-: TCL is useful in handling transactions in the database. Transactions provide data moral in a multi-user environment. This command can roll back and save data transformation in the database. Some useful commands for TCL are COMMIT, ROLLBACK, SAVEPOINT, and SET TRANSACTION.
- COMMIT-: This command is useful to save or use the change in the database.
- ROLLBACK-: We can use it to undo the modification.
- SAVEPOINT-: We can apply this command temporarily to save a transaction. Through this transaction can roll back to this point whenever it is required.
At last, we state that SQL commands give instruction that is useful to communicate with the database. This performs some special tasks like writing, modifying, updating, etc., data from data the table. This is an actual step to moving ahead in your journey to becoming a SQL expert. Many institutes for SQL Training in Delhi will help you to gain knowledge about this particular training course.