作者kikilalagirl (kikilala)
看板Database
标题[讨论] three-schema architecture ?
时间Tue Jan 12 02:47:24 2016
Three-schema architecture 分为
1. External schema
2. Conceptual schema
3. Internal schema
请问甚麽样的语法 , 才能各自代表每一层呢 ?
CREATE TABLESPACE 代表 Internal schema ?
CREATE TABLE 代表 Conceptual schema ?
什麽样的语法代表 External schema 呢 ?
-----
CREATE TABLESPACE "IMAGEDATA"
NOLOGGING
DATAFILE
'D:"oracle"oradata"DATA01.dbf' SIZE 2000M,
'D:"oracle"oradata"DATA02.dbf' SIZE 2000M,
'D:"oracle"oradata"DATA03.dbf' SIZE 2000M,
'D:"oracle"oradata"DATA04.dbf' SIZE 2000M,
'D:"oracle"oradata"DATA05.dbf' SIZE 2000M
EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO
-----
CREATE TABLE Customer
( First_Name char(50),
Last_Name char(50),
Address char(50),
City char(50),
Country char(25),
Birth_Date datetime
);
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