Cardinality in structured query language (SQL) can be defined as the mean of unique data value present in certain column. Cardinality is also known as data cardinality or attribute of database table. There are three types of data cardinality High Data Cardinality Normal Data Cardinality Low Data Cardinality Read: All about SQL CREATE USER Query […]
What is Cost Based Optimizer?
Query optimizer in RDBMS can be defined as a part of SQL program which is used to analyze the best way to run a SQL query. The query optimizers are used to improve the efficiency of the SQL statements. Related: SQL & .NET Interview questions and Answers What is Cost based Optimizer? Cost based optimizer […]
Tuning SQL Index
In a database, SQL indexes are used to accelerate the query searching process. But using indexes will consume a lot of space and require regular maintenance. The regular maintenance on indexes will ensure the smooth running of database. This article will provide you some guidelines and tips to properly utilize indexes without any hassles. MySQL […]
SQL Three Valued Logic
The logic used by SQL is complicated because it uses three valued logic instead of two. Two valued logic is based on boolean algebra which return two value namely truth and fale. Boolean algebra can be operated using three basic operator namely AND, OR and NOT. If a unknown NULL value is used in boolean […]
SQL REVOKE Command
REVOKE command in SQL is used to remove one or more privileges assigned to a database user. The basic syntax for REVOKE command is given below. REVOKE priv_type [(col_list)] [, priv_type [(col_list)]]… ON [obj_typ] priv_level FROM user [, user_name] The list of privileges that need to be revoked is mentioned right after the REVOKE statement. […]
SQL GRANT Command
GRANT command in SQL is used grant one or more privileges to a database user. The basic syntax for GRANT statement in a SQL is given below. GRANT privilege_name ON object_name TO {user_name |PUBLIC |role_name} [WITH GRANT OPTION]; privilege_name: is the privilege provided to the user. The access right for a user includes ALL, SELECT […]
All about SQL CREATE USER Query
The CREATE USER statement allows us to create a new user account in the SQL database. Almost all the database platforms provide GUI to create new users. However CREATE USER statement is a standard in SQL and basic syntax for creating user in SQL is given below, CREATE USER username [IDENTIFIED BY password] [other options]; […]