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ITEC 313 Database Programming. Bits of SQL. Objectives. Review Select Statement Creating tables Learn how to create and use Sequence View Learn how to Grant/Revoke priveleges. Syntax of SELECT. SELECT [ALL | DISTINCT] select-list FROM table-reference-list
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ITEC 313 Database Programming Bits of SQL
Objectives • Review • Select Statement • Creating tables • Learn how to create and use • Sequence • View • Learn how to Grant/Revoke priveleges
Syntax of SELECT SELECT [ALL | DISTINCT] select-list FROM table-reference-list [WHERE search-condition] [GROUP BY column-name [, column-name]... ] [HAVING search-condition] [ [UNION | UNION ALL |INTERSECT | MINUS] select-statement ] ... [ORDER BY {unsigned integer | column-name} [ASC|DESC]]
Syntax of SELECT • select-list : • columns, expressions, fixed values. • Include aliases • table-reference-list • Tables, views, subqueries(inline view) • search-condition • Conditions involving columns, fixed values, subqueries
Syntax of Create Table Statement CREATE TABLE table-name ( Column-name data-type [column-constraints] [DEFAULT default-value] {, Column-name data-type [column-constraints] [DEFAULT default-value] } [table-constraint {, table-constraint}] )
Format of Alter Table Statement ALTER TABLE table-name ADD column-declaration [ column-constraints] Or ALTER TABLE table-name ADD table-constraints Or ALTER TABLE table name MODIFY column
Sequences • autonumber field • independent of a column • An object in Oracle that is used to generate a number sequence • Useful for creating a unique number to act as a primary key
Format of Sequence CREATE SEQUENCE sequence_name MINVALUE value MAXVALUE value START WITH value INCREMENT BY value CACHE value;
Views • Representation of an sql statement • Only the code to create the view is stored in the data dictionary NOT the actual data • Used for • Improving efficiency • Improving Security • Hiding details/columns from end users
Syntax of VIEW CREATE VIEW view-name AS Select-statement
Grant/Revoke • Privileges are of two types : • System Privileges • Object privileges • GRANT : allows users access to your objects. • INSERT, DELETE, UPDATE, SELECT, EXECUTE privileges may be granted to other users • REVOKE : removes existing privileges on an object from other users.
SYNTAX of Grant/Revoke • GRANT INSERT, DELETE, UPDATE, SELECT, EXECUTE|ALL on object-name TO user-list|ROLE|PUBLIC; • REVOKE INSERT, DELETE, UPDATE, SELECT, EXECUTE | ALL on object-name FROM user-list|ROLE|PUBLIC; • ROLE: contaimns groups of users determined by the DBA • PUBLIC : A system ROLE that contains all users of the database