Database and SQL

Alter table command is used in SQL to alter the definition of already existing table.

Drop is used to delete table/view/synonym in SQL.

A default value can be specified for a column using the default clause.

This function returns sign of a given number.

This function is used to convert a given string to equivalent number in SQL.

This type of entity constraint in DBMS requires that an entity belongs to no more than one lower level entity set.

In a database relation, when one or more fields serve as primary key, then such a key is called composite key.

This object in SQL is a predicate expressing a condition that we wish the database always to satisfy.

This normal form in DBMS states that every determinant in the database is a candidate key.

This is the first step in executing a SQL query in DBMS as once a query is entered into the system its meaning is to be clearly understood by the compiler.

This type of integrity constraint in DBMS is also called as attribute integrity in which a column is assigned the possible value only.

This is a methodology of optimising a group of SQL queries altogether with the help of common sub-expressions to save cost and time.

Data segment compression should be used with highly redundant data, such as tables with many foreign keys. It can also speed up query execution.

It is equivalent to the given EJB sql expression.

This is the first step for using explicitly defined cursors within PL/SQL that enables a user to define the cursor and assign a name to it.