by Dinesh Thakur Category: SQL Tutorials

The SQL DISTINCT query is used with the SELECT keyword retrieves only unique data values depending on the fields you have specified after it. To illustrate it we use emp table as shown below.

Select ename from EMP;
 
by Dinesh Thakur Category: SQL Tutorials

The DELETE statement is used to delete rows in a table. To do so, we can use the DELETE FROM command. An SQL DELETE statement removes one or more records from a table. A subset may be defined for deletion using a condition, otherwise all records are removed.

 
by Dinesh Thakur Category: SQL Tutorials

Oracle uses work areas to execute SQL statements and store processing information. A PL/SQL construct called a CURSOR lets you name a work area and access its stored information. A Cursor in its simplest form can be thought of as a pointer to the records in database table or a virtual table represented by the result of a SELECT statement.



 
by Dinesh Thakur Category: SQL Tutorials

The create table statement is used to create a new table. The CREATE TABLE statement defines a table. The definition must include its name and the names and attributes of its columns. The definition can include other attributes of the table, such as its primary key or check constraints. This statement comes under the DDL statement.

 
by Dinesh Thakur Category: SQL Tutorials

A sequence is a database object that generates numbers in sequential order. Applications most often use these numbers when they require a unique value in a table such as primary key values. Some database management systems use an "auto number" concept or "auto increment" setting on numeric column types. Both the auto numbering columns and sequences provide a unique number in sequence used for a unique identifier.



 
by Dinesh Thakur Category: SQL Tutorials

SQL (Standard Query Language) is a language for manipulating databases developed in the 70s by IBM. All data management systems use SQL to access data or to communicate with a data server. RDBMS is the core platform for SQL, and for all other modern database languages such as  Oracle, MS SQL Server, IBM DB2, MySQL, and Microsoft Access, PostgreSQL, SQLite, Firebird, and many more. SQL (Standard Query Language) is born as a result of the mathematical work of Codd, who founded the work of relational databases, three types of manipulations on the database:



 


About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.