orale培训教材包括了所有的sql说明和实例

				--CHECK使用单一条件
				
				
				CREATE TABLE sm_emp_check(
				empid  VARCHAR2(3),
				name   VARCHAR2(10),
				salary NUMBER(8,2)  CHECK (salary				
				
				INSERT INTO sm_emp_check VALUES('001', 'JACK', 100);
				INSERT INTO sm_emp_check VALUES('002', 'JACK2', 101);
				
				INSERT INTO sm_emp_check VALUES('003', 'JACK3', 10000);
				ERROR 位于第 1 行:
				
				
				CREATE TABLE sm_emp_check(
				empid  VARCHAR2(3),
				name   VARCHAR2(10),
				salary NUMBER(8,2)  CHECK ( 100				--error:100				
				
				DROP TABLE sm_emp_check;
				CREATE TABLE sm_emp_check(
				empid  VARCHAR2(3),
				name   VARCHAR2(10),
				salary NUMBER(8,2)  CHECK ( 100				INSERT INTO sm_emp_check VALUES('001', 'JACK', 100);
				INSERT INTO sm_emp_check VALUES('002', 'JACK2', 101);
				INSERT INTO sm_emp_check VALUES('003', 'JACK3', 10000);
				
				--NULL = SALAY
				INSERT INTO sm_emp_check VALUES('003', 'JACK3', NULL);
				DROP TABLE sm_emp_check;
				CREATE TABLE sm_emp_check(
				empid  VARCHAR2(3),
				name   VARCHAR2(10),
				salary NUMBER(8,2)  CHECK ( 100				INSERT INTO sm_emp_check VALUES('003', 'JACK3', NULL);
				
				
				
				ALTER TABLE plsql101_purchase ADD ( 
				     CONSTRAINT reasonable_date CHECK(
				          purchase_date IS NOT NULL
				          AND
				          TO_CHAR(purchase_date, 'YYYY-MM-DD') >= '2000-06-30'
				          )
				     )
				;
				
				INSERT INTO plsql101_purchase VALUES (
				     'Small Widget', 'GA', '28-2月-00', 10);