The SQL UNIQUE constraint is a type of data integrity constraint that ensures that the values in a column or set of columns are unique and not duplicated within the same table. The UNIQUE constraint is useful for ensuring that specific columns in a database table are only associated with unique data values. It is […]
SQL NOT NULL constraint is used to enforce a column to not have a null value. This constraint ensures that a value must be entered for a column, helping to maintain the accuracy and consistency of the data in a database. Why Use the NOT NULL Constraint The NOT NULL constraint is important because it […]
SQL Constraints are used to specify rules and restrictions on the data that can be stored in a database. Constraints are used to ensure data integrity, which helps to maintain the accuracy and consistency of the data in a database. The constraints can be specified while creating a table or can be added later using […]
SQL ALTER TABLE is a statement used in SQL to modify the structure of an existing table in a database. With the ALTER TABLE statement, you can add, delete, modify columns in the table, change the name of the table, and perform various other structural changes. Adding a Column to a Table To add a […]
SQL DROP TABLE is a statement used in SQL to delete an existing table from a database. The DROP TABLE statement is used when you no longer need the data in a table and want to remove it from the database. Deleting a Table To delete a table, you must specify the name of the […]
SQL CREATE TABLE is a statement used in SQL to create a new table. A table is a database object that consists of columns and rows, where data is stored. The CREATE TABLE statement is used to define the columns and their data types, as well as any constraints that should be applied to the […]
Backing up a database is an important task in database management as it ensures the availability of data in case of any unforeseen incidents, such as hardware failure, software malfunction, or accidental deletion of data. In SQL, the backup process involves creating a copy of the database and storing it in a safe location. Why […]
In SQL, the DROP DATABASE statement is used to remove an existing database from a relational database management system (RDBMS). This statement permanently deletes the database and all its objects, including tables, views, stored procedures, and functions. As a result, it is an extremely powerful command that must be used with caution, as once a […]
SQL CREATE DATABASE is a statement used to create a new database in SQL. A database is a collection of tables and other database objects, used to store and manage data. The CREATE DATABASE statement is used to create a new database with a specified name. Syntax for SQL CREATE DATABASE The basic syntax for […]
SQL operators are symbols used in SQL statements to perform operations, such as mathematical or logical operations. These operations can include comparisons, arithmetics, and logical evaluations. Operators are used to manipulate and process data within a database to produce a desired result. Types of SQL Operators SQL operators can be broadly classified into the following […]
