Category: Table

SQL Constraints SQL Constraints are the rules applied to a data columns or the complete table to limit the type of data that can go into a table. When you try to perform any INSERT, UPDATE, or DELETE operation on the table, RDBMS will check whether that data violates any existing constraints and if there…

The SQL DELETE is a command of Data Manipulation Language (DML), so it does not delete or modify the table structure but it delete only the data contained within the table. Therefore, any constraints, indexes, or triggers defined in the table will still exist after you delete data from it. SQL DELETE TABLE Statement The SQL DELETE TABLE statement…

SQL provides command to DROP an existing table completely in a database. Once SQL DROP command is issued then there is no way back to recover the table including its data, so be careful before issuing this command in production system. The SQL DROP Table Statement The SQL DROP TABLE statement is a Data Definition Language (DDL)…

SQL − ALTER TABLE Statement The SQL ALTER TABLE command is a part of Data Definition Language (DDL) and modifies the structure of a table. The ALTER TABLE command can add or delete columns, create or destroy indexes, change the type of existing columns, or rename columns or the table itself. The ALTER TABLE command can also…

What are Temporary Tables? Temporary tables are pretty much what their name describes: they are the tables which are created in a database to store temporary data. We can perform SQL operations similar to the operations on permanent tables like CREATE, UPDATE, DELETE, INSERT, JOIN, etc. But these tables will be automatically deleted once the…

There may be a situation when you need an exact copy of a table with the same columns, attributes, indexes, default values and so forth. Instead of spending time on creating the exact same version of an existing table, you can create a clone of the existing table. SQL Cloning Operation allows to create the exact copy…

SQL provides command to TRUNCATE a table completely in one go instead of deleting table records one by one which will be very time consuming and cumbersome process. The SQL TRUNCATE TABLE Statement The SQL TRUNCATE TABLE command is used to empty a table. This command is a sequence of DROP TABLE and CREATE TABLE statements and…

SQL provides two ways to rename an MySQL table. You can use either SQL RENAME TABLE or ALTER TABLE statement to change a table name in MySQL RDBMS. The SQL RENAME TABLE Statement You can change a MySQL table name using SQL RENAME TABLE statement. Syntax Following is the syntax of the SQL RENAME TABLE Statement −…

There are several instances when you need to retrieve a list of tables from your database. This could be done for testing purposes, to identify any existing tables before adding or removing any, or for any other reason. This tutorial will discuss how we can list down all the table in MySQL, SQL Server and…

This tutorial will teach you how to use SQL to create tables in RDBMS. We use CREATE TABLE command to create a Table in a Database. In RDBMS, Database tables are used to store the data in the form of some structures (fields and records). Here, a field is a column defining the type of data to be stored…