What are the objects in oracle?

最新推荐文章于 2025-12-01 17:13:11 发布

转载最新推荐文章于 2025-12-01 17:13:11 发布 · 237 阅读

文章标签：

#table #oracle #query #object #cache #each

本文详细介绍了Oracle数据库中的几种核心对象，包括Table（表）、View（视图）、Synonym（同义词）和Sequence（序列）。表用于存储数据，每个表由具有唯一名称和数据类型的列组成；视图作为查询结果的表示，可以加快数据访问速度；同义词为表、视图等对象提供替代名称；序列用于生成唯一的数值系列，通常用作主键。

Table, Views, Index, Synonym and Sequence are the objects of oracle.

Table: An oracle table is used to store data. A table has columns with each column having a unique name and a data type.

Example:
CREATE TABLE TABLE_NAME
(
COLUMN1 DATATYPE1,
COLUMN2 DATATYPE2
);

View: A view in oracle is a representation of data. Data here means results of a query that is stored in order to be reused for faster access. The view below creates a view view_std without actually giving any result. When this view is query, oracle executes a query.

Example:
CREATE VIEW view_std
AS
SELECT stdid FROM student;

Synonym: A synonym is an alternate name given to an Oracle object like Table, view, stored procedure etc. Example: Create a public synonym (accessible to all users).

Example:
Create public synonym suppliers
for app.suppliers;

Sequence: A sequence is used to create a unique series of number usually for a primary key. Example:- The sequence below starts with 1 up to 999 and is incremented by 1. it caches up to 20 values.

Example:
CREATE SEQUENCE student_seq
             MINVALUE 1
             MAXVALUE 999
             START WITH 1
             INCREMENT BY 1
             CACHE 20;