Question 331 – What is the use of RESTRICT Keyword in SQL?

• It specifies that table should not be dropped if any dependencies (i.e. triggers, stored procedure, primary key, foreign key etc) exist.
• Therefore, if there are dependencies then error is generated and the object is not dropped.

Question 332 – What is the use of DML in SQL?

It is abbreviation of Data Manipulation Language. It is used to retrieve, store, modify, delete, insert and update in database. Examples: SELECT, INSERT, UPDATE, DELETE, MERGE, CALL, EXPLAIN PLAN, LOCK TABLE

Question 333 – What is the use of DDL in SQL?

It is abbreviation of Data Definition Language. It is used to create and modify the structure of database objects in database. Examples: CREATE, ALTER, DROP, TRUNCATE, COMMENT, RENAME

Question 334 – What is the use of DCL in SQL?

It is abbreviation of Data Control Language. It is used to create roles, permissions, and referential integrity as well it is used to control access to database by securing it. Examples: GRANT, REVOKE statements

Question 335 – What is the use of TCL in SQL?

It is abbreviation of Transactional Control Language. It is used to manage different transactions occurring within a database. Examples: COMMIT, ROLLBACK, SAVEPOINT,  SET TRANSACTION statements.

Question 336 – What is the use of Wildcards in SQL?

• It can substitute for one or more characters when searching for data in a database.
• SQL wildcards must be used with the SQL LIKE operator.
• With SQL, the following wildcards can be used %, -, [charlist] etc.

Question 337 – What is the use of Aggregate functions?

• It perform a calculation on a set of values and return a single value.
• Except for COUNT, aggregate functions ignore null values.
• Aggregate functions are frequently used with the GROUP BY clause of the SELECT statement.
• Aggregate functions can be used as expressions only in the following:
• The select list of a SELECT statement (either a SubQuery or an outer query).
• A COMPUTE or COMPUTE BY clause.
• A HAVING clause.

Question 338 – What is the use of ROLLUP in SQL?

• ROLLUP clause is used to do aggregate operation on multiple levels in hierarchy.
• It work with the “Group By ” clause its main functioning comes into existence when we use Group by.
  We can get sub-total of row by using the Rollup function.
• When result is return by Group By class first row display grand total or we can say that the main total.
• Syntax:- select firstcolumn, secondcolumn, sum(thirdcolumn) from tablename group by firstcolumn, secondcolumn with rollup order by firstcolumn.

Question 339 – What is the use of CUBE in SQL?

• The CUBE operator generates a result set that is a multidimensional cube.
• It is a result set that contains a cross tabulation of all the possible combinations of the dimensions.
• The CUBE operator is specified in the GROUP BY clause of a SELECT statement.
• The select list contains the dimension columns and aggregate function expressions.
• The GROUP BY specifies the dimension columns and the keywords WITH CUBE.

Question 340 – What are the Differences between CUBE and ROLLUP?

• CUBE generates a result set that shows aggregates for all combinations of values in the selected columns.
• ROLLUP generates a result set that shows aggregates for a hierarchy of values in the selected columns.

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