| SQL |
| SQL is a programming language for querying and modifying data and managing databases . SQL allows the retrieval, insertion, updating, and deletion of data. A database management system also includes management and administrative functions. Most -- if not all -- implementations also include a command-line Interface (SQL/CLI) that allows for the entry and execution of the language commands, as opposed to only providing an API intended for access from a GUI.
The first version of SQL was developed at IBM by Donald D. Chamberlin and Raymond F. Boyce in the early 1970s. This version, initially called SEQUEL, was designed to manipulate and retrieve data stored in IBM's original relational database product, System R. IBM patented their version of SQL in 1985[4], while the SQL language was not formally standardized until 1986, by the American National Standards Institute (ANSI) as SQL-86. Subsequent versions of the SQL standard have been released by ANSI and as International Organization for Standardization (ISO) standards |
Structured Query Language (SQL) is a language that provides
an interface to relational database systems. |
DDL |
| Data Definition Language (DDL) statements areused for creating and modifying
tables and other database structures.
CREATE - to create objects in the database
ALTER - alters the structure of the database
DROP - delete objects from the database
TRUNCATE - remove all records from a table, including all spaces allocated for the records are removed
COMMENT - add comments to the data dictionary
RENAME - rename an object |
DML |
Data Manipulation Language (DML) statements are used for managing data within schema objects.
SELECT - retrieve data from the a database
INSERT - insert data into a table
UPDATE - updates existing data within a table
DELETE - deletes all records from a table, the space for the records remain
MERGE - UPSERT operation (insert or update)
CALL - call a PL/SQL or Java subprogram
EXPLAIN PLAN - explain access path to data
LOCK TABLE - control concurrency |
DCL |
Data Control Language (DCL) statements
GRANT - gives user's access privileges to database
REVOKE - withdraw access privileges given with the GRANT command |
TCL |
Transaction Control (TCL) statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions.
COMMIT - save work done
SAVEPOINT - identify a point in a transaction to which you can later roll back
ROLLBACK - restore database to original since the last COMMIT
SET TRANSACTION - Change transaction options like isolation level and what rollback segment to use |
| |
|
| Table of Content |
 |
Truncate,Delete and Drop |
|
Insert and Delete |
|
Create Table |
|
SQL Constraints |
|
Alter Table Constraints |
|
|
|
| |
| |
| |
|
