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标题: 【课堂笔记】【SQL】9.Using DDL Statements to Create and Manage Tables [打印本页]

作者: 5dm 时间: 2012-10-30 15:46
标题: 【课堂笔记】【SQL】9.Using DDL Statements to Create and Manage Tables

Database Objects 包括：

TABLE,VIEW,SEQUENCE,INDEX,SYNONYM

Data Types

Data Type

Description

VARCHAR2(size)

Variable-length character data

CHAR(size)

Fixed-length character data

NUMBER(p,s)

Variable-length numeric data

DATE

Date and time values

LONG

Variable-length character data (up to 2 GB)

CLOB

Character data (up to 4 GB)

RAW and LONG RAW

Raw binary data

BLOB

Binary data (up to 4 GB)

BFILE

Binary data stored in an external file (up to 4 GB)

ROWID

A base-64 number system representing the unique address of a row in its table

作者: 5dm 时间: 2012-10-30 15:46

Datetime Data Types

Data Type

Description

TIMESTAMP

Date with fractional seconds含微秒

INTERVAL YEAR TO MONTH

Stored as an interval of yearsand months记录两个时间的时间年月间隔

INTERVAL DAY TO SECOND

Stored as an interval of days, hours, minutes, and seconds记录两个时间的时间天秒间隔

Constraints包括：

–NOT NULL

–UNIQUE

–PRIMARY KEY

–FOREIGN KEY

–CHECK

约束名默认为：SYS_Cn……

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Data Type	Description
VARCHAR2(size)	Variable-length character data
CHAR(size)	Fixed-length character data
NUMBER(p,s)	Variable-length numeric data
DATE	Date and time values
LONG	Variable-length character data (up to 2 GB)
CLOB	Character data (up to 4 GB)
RAW and LONG RAW	Raw binary data
BLOB	Binary data (up to 4 GB)
BFILE	Binary data stored in an external file (up to 4 GB)
ROWID	A base-64 number system representing the unique address of a row in its table

Data Type	Description
TIMESTAMP	Date with fractional seconds含微秒
INTERVAL YEAR TO MONTH	Stored as an interval of yearsand months记录两个时间的时间年月间隔
INTERVAL DAY TO SECOND	Stored as an interval of days, hours, minutes, and seconds记录两个时间的时间天秒间隔