按条件检查 CHECK (条件) 外键REFERENCES 表名(字段名) 3. 创建表的例子 CREATE TABLE DEPT( EPTNO NUMBER(2) CONSTRAINT PK_DEPT PRIMARY KEY, DNAME VARCHAR2(14), LOC VARCHAR2(13)) ; CREATE TABLE region( ID number(2) NOT NULL PRIMARY KEY, postcode number(6) default '0' NOT NULL, areanam...
First, drop the suppliers table: DROP TABLE suppliers; Code language: SQL (Structured Query Language) (sql) Second, recreate the suppliers table with a foreign key constraint: CREATE TABLE suppliers ( supplier_id NUMBER GENERATED BY DEFAULT AS IDENTITY, supplier_name VARCHAR2(255) NOT NULL, gro...
create table emp0(id number ,name varchar(8) ,constraint fk_nam1e foreign key(id,name) references emp9(id,name1)); --主键另外写法 create table emp2(id number,name varchar(8),id1 number, constraint pk_id primary key(id),constraint fk_name foreign key(id1) references emp(id)) --c...
5 create table emp1(id number references emp(id),name varchar(8)); 6 --复合外键 7 create table emp0(id number ,name varchar(8) ,constraint fk_nam1e foreign key(id,name) references emp9(id,name1)); 8 9 --主键另外写法 10 create table emp2(id number,name varchar(8),id1 number...
CREATE TABLE book ( bid NUMBER PRIMARY KEY NOT NULL, bname VARCHAR(30), bprice NUMBER(5,2), pid VARCHAR2(18) REFERENCES person(pid) -- 通过references 引入外键,这里的外键是主表 -- constraint person_book_pid_fk foreign key(pid) references person(pid) ); 这样就完成了主外键的操作,但是有...
create table stuinfo( id number primary key, name varchar2(30) not null, brithday date ); insert into stuinfo values(1,'诗书画唱',to_date('2020-06-06','yyyy-mm-dd')); insert into stuinfo values(2,'三连',to_date('2020-07-07','yyyy-mm-dd')); ...
For example, you can execute theCREATE TABLEstatement that creates the invoices table as many times as you want , with theIF NOT EXISTSoption: CREATETABLEIFNOTEXISTSinvoices ( invoice_noNUMBERPRIMARYKEY, invoice_dateDATENOTNULL, customer_idNUMBERNOTNULL, ...
truncate table 删除表数据(不可以回滚) 2、创建表: -- 创建表 create table sclass( cid int primary key, cname varchar(10) ) create tableJava( ssid int primary key, -- 主键约束 sname varchar2(20) unique, -- 唯一约束 ssex char(5) check(ssex in ('男','女')),--检查约束,检查输入的...
create table student_info --学生信息表 (id number(4) primary key --主键 ,sno number(4) --学号 ,sname varchar2(20) not null --姓名 ,sex varchar2(2) check(sex = '男'or sex = '女') --性别 ,graduated_year number(4) --毕业年龄 ...
alter table table_name drop columnRS_SFTG; 序列参数说明 代码语言:javascript 代码运行次数:0 运行 AI代码解释 CREATESEQUENCESEQNAME//序列名字INCREMENTBY1//每次自增1, 也可写非0的任何整数,表示自增,或自减STARTWITH1//以该值开始自增或自减MAXVALUE1.0E20//最大值;设置NOMAXVALUE表示无最大值MINVALUE...