Oracle PL/SQL Tutorial/Table/Unique — различия между версиями
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Текущая версия на 13:05, 26 мая 2010
Содержание
Adding a UNIQUE Constraint
<source lang="sql">
SQL> -- create demo table SQL> create table myTable(
2 id NUMBER(2), 3 value NUMBER(6,2) 4 ) 5 /
Table created.
SQL> SQL> ALTER TABLE myTable
2 ADD CONSTRAINT uq UNIQUE (id);
Table altered. SQL> SQL> SQL> drop table myTable
2 /
Table dropped. SQL></source>
Add unique constaint to new added column
<source lang="sql">
SQL> -- create demo table SQL> create table Employee(
2 ID VARCHAR2(4 BYTE) NOT NULL primary key, 3 First_Name VARCHAR2(10 BYTE), 4 Last_Name VARCHAR2(10 BYTE), 5 Start_Date DATE, 6 End_Date DATE, 7 Salary Number(8,2), 8 City VARCHAR2(10 BYTE), 9 Description VARCHAR2(15 BYTE) 10 ) 11 /
Table created. SQL> SQL> -- prepare data SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values ("01","Jason", "Martin", to_date("19960725","YYYYMMDD"), to_date("20060725","YYYYMMDD"), 1234.56, "Toronto", "Programmer")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("02","Alison", "Mathews", to_date("19760321","YYYYMMDD"), to_date("19860221","YYYYMMDD"), 6661.78, "Vancouver","Tester")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("03","James", "Smith", to_date("19781212","YYYYMMDD"), to_date("19900315","YYYYMMDD"), 6544.78, "Vancouver","Tester")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("04","Celia", "Rice", to_date("19821024","YYYYMMDD"), to_date("19990421","YYYYMMDD"), 2344.78, "Vancouver","Manager")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("05","Robert", "Black", to_date("19840115","YYYYMMDD"), to_date("19980808","YYYYMMDD"), 2334.78, "Vancouver","Tester")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("06","Linda", "Green", to_date("19870730","YYYYMMDD"), to_date("19960104","YYYYMMDD"), 4322.78,"New York", "Tester")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("07","David", "Larry", to_date("19901231","YYYYMMDD"), to_date("19980212","YYYYMMDD"), 7897.78,"New York", "Manager")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("08","James", "Cat", to_date("19960917","YYYYMMDD"), to_date("20020415","YYYYMMDD"), 1232.78,"Vancouver", "Tester")
3 /
1 row created. SQL> SQL> SQL> SQL> -- display data in the table SQL> select * from Employee
2 /
ID FIRST_NAME LAST_NAME START_DAT END_DATE SALARY CITY DESCRIPTION
-------------------- -------------------- --------- --------- ---------- ---------- ---------------
01 Jason Martin 25-JUL-96 25-JUL-06 1234.56 Toronto Programmer 02 Alison Mathews 21-MAR-76 21-FEB-86 6661.78 Vancouver Tester 03 James Smith 12-DEC-78 15-MAR-90 6544.78 Vancouver Tester 04 Celia Rice 24-OCT-82 21-APR-99 2344.78 Vancouver Manager 05 Robert Black 15-JAN-84 08-AUG-98 2334.78 Vancouver Tester 06 Linda Green 30-JUL-87 04-JAN-96 4322.78 New York Tester 07 David Larry 31-DEC-90 12-FEB-98 7897.78 New York Manager
ID FIRST_NAME LAST_NAME START_DAT END_DATE SALARY CITY DESCRIPTION
-------------------- -------------------- --------- --------- ---------- ---------- ---------------
08 James Cat 17-SEP-96 15-APR-02 1232.78 Vancouver Tester 8 rows selected. SQL> SQL> SQL> alter table employee
2 add ( 3 ssn varchar2( 9 ) 4 );
Table altered. SQL> SQL> alter table employee
2 add constraint employee_ssn_uk 3 unique( ssn );
Table altered. SQL> SQL> SQL> SQL> -- clean the table SQL> drop table Employee
2 /
Table dropped.</source>
Add unique constraint across more than one columns
<source lang="sql">
SQL> SQL> SQL> SQL> -- create demo table SQL> create table Employee(
2 ID VARCHAR2(4 BYTE) NOT NULL primary key, 3 First_Name VARCHAR2(10 BYTE), 4 Last_Name VARCHAR2(10 BYTE), 5 Start_Date DATE, 6 End_Date DATE, 7 Salary Number(8,2), 8 City VARCHAR2(10 BYTE), 9 Description VARCHAR2(15 BYTE) 10 ) 11 /
Table created. SQL> SQL> -- prepare data SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values ("01","Jason", "Martin", to_date("19960725","YYYYMMDD"), to_date("20060725","YYYYMMDD"), 1234.56, "Toronto", "Programmer")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("02","Alison", "Mathews", to_date("19760321","YYYYMMDD"), to_date("19860221","YYYYMMDD"), 6661.78, "Vancouver","Tester")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("03","James", "Smith", to_date("19781212","YYYYMMDD"), to_date("19900315","YYYYMMDD"), 6544.78, "Vancouver","Tester")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("04","Celia", "Rice", to_date("19821024","YYYYMMDD"), to_date("19990421","YYYYMMDD"), 2344.78, "Vancouver","Manager")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("05","Robert", "Black", to_date("19840115","YYYYMMDD"), to_date("19980808","YYYYMMDD"), 2334.78, "Vancouver","Tester")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("06","Linda", "Green", to_date("19870730","YYYYMMDD"), to_date("19960104","YYYYMMDD"), 4322.78,"New York", "Tester")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("07","David", "Larry", to_date("19901231","YYYYMMDD"), to_date("19980212","YYYYMMDD"), 7897.78,"New York", "Manager")
3 /
1 row created. SQL> insert into Employee(ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
2 values("08","James", "Cat", to_date("19960917","YYYYMMDD"), to_date("20020415","YYYYMMDD"), 1232.78,"Vancouver", "Tester")
3 /
1 row created. SQL> SQL> SQL> SQL> -- display data in the table SQL> select * from Employee
2 /
ID FIRST_NAME LAST_NAME START_DAT END_DATE SALARY CITY DESCRIPTION
---------- ---------- --------- --------- ---------- ---------- ---------------
01 Jason Martin 25-JUL-96 25-JUL-06 1234.56 Toronto Programmer 02 Alison Mathews 21-MAR-76 21-FEB-86 6661.78 Vancouver Tester 03 James Smith 12-DEC-78 15-MAR-90 6544.78 Vancouver Tester 04 Celia Rice 24-OCT-82 21-APR-99 2344.78 Vancouver Manager 05 Robert Black 15-JAN-84 08-AUG-98 2334.78 Vancouver Tester 06 Linda Green 30-JUL-87 04-JAN-96 4322.78 New York Tester 07 David Larry 31-DEC-90 12-FEB-98 7897.78 New York Manager 08 James Cat 17-SEP-96 15-APR-02 1232.78 Vancouver Tester 8 rows selected. SQL> SQL> SQL> ALTER TABLE employee
2 ADD CONSTRAINT emp_unique UNIQUE ( 3 first_name, 4 last_name, 5 start_date 6 );
Table altered. SQL> SQL> SQL> ALTER TABLE employee
2 DROP CONSTRAINT emp_unique;
Table altered. SQL> SQL> SQL> -- clean the table SQL> drop table Employee
2 /
Table dropped. SQL> SQL></source>
Add unique constraints
<source lang="sql">
SQL> SQL> SQL> set echo off SQL> create table emp(
2 emp_id integer primary key using index (create index pk_idx on emp(emp_id) ) 3 ,lastname varchar2(20) constraint lastname_create_nn not null 4 ,firstname varchar2(15) constraint firstname_create_nn not null 5 ,midinit varchar2(1) 6 ,street varchar2(30) 7 ,city varchar2(20) 8 ,state varchar2(2) 9 ,zip varchar2(5) 10 ,shortZipCode varchar2(4) 11 ,area_code varchar2(3) 12 ,phone varchar2(8) 13 ,company_name varchar2(50) 14 ,constraint unique_emp_phone unique(phone) using index (create index emp_phone_u_idx on emp(phone)) 15 );
Table created. SQL> SQL> select index_name, table_name, column_name from user_ind_columns where table_name = "emp"; no rows selected SQL> SQL> select constraint_name, table_name, column_name from user_cons_columns where table_name = "emp"; no rows selected SQL> SQL> drop table emp cascade constraints; Table dropped.</source>
Add unique constraints for combined columns
<source lang="sql">
SQL> SQL> SQL> CREATE TABLE person (
2 person_code VARCHAR2(3) PRIMARY KEY, 3 first_name VARCHAR2(15), 4 last_name VARCHAR2(20), 5 hire_date DATE 6 );
Table created. SQL> SQL> ALTER TABLE person
2 ADD CONSTRAINT person_unique UNIQUE ( 3 first_name, 4 last_name, 5 hire_date 6 );
Table altered. SQL> SQL> SQL> drop table person; Table dropped. SQL> SQL></source>
ORA-00001: unique constraint (JAVA2S.JOB_UNIQUE_IN_TEAMID) violated
<source lang="sql">
SQL> create table emp
2 (emp_ID number primary key,
3 teamid number,
4 job varchar2(100),
5 status varchar2(20) check (status in ("ACTIVE", "INACTIVE"))
6 );
Table created. SQL> SQL> SQL> create UNIQUE index job_unique_in_teamid on emp
2 ( case when status = "ACTIVE" then teamid else null end, 3 case when status = "ACTIVE" then job else null end 4 ) 5 /
Index created. SQL> SQL> insert into emp(emp_id,teamid,job,status)values( 1, 10, "a", "ACTIVE" ); 1 row created. SQL> SQL> insert into emp(emp_id,teamid,job,status)values( 2, 10, "a", "ACTIVE" ); insert into emp(emp_id,teamid,job,status)values( 2, 10, "a", "ACTIVE" )
ERROR at line 1: ORA-00001: unique constraint (sqle.JOB_UNIQUE_IN_TEAMID) violated
SQL> SQL> SQL> update emp
2 set status = "INACTIVE" 3 where emp_id = 1 4 and teamid = 10 5 and status = "ACTIVE";
1 row updated. SQL> SQL> SQL> insert into emp(emp_id,teamid,job,status)values( 2, 10, "a", "ACTIVE" ); 1 row created. SQL> SQL> drop table emp; Table dropped. SQL></source>
Violate an unique constraints
<source lang="sql">
SQL> SQL> CREATE TABLE person (
2 person_code VARCHAR2(3) PRIMARY KEY, 3 first_name VARCHAR2(15), 4 last_name VARCHAR2(20), 5 hire_date DATE 6 );
Table created. SQL> SQL> ALTER TABLE person
2 ADD CONSTRAINT person_unique UNIQUE ( 3 first_name, 4 last_name, 5 hire_date 6 );
Table altered. SQL> SQL> SQL> SQL> INSERT INTO person VALUES ("CA", "Chase", "At", "01-FEB-02"); 1 row created. SQL> INSERT INTO person VALUES ("GA", "Chase", "At", "01-FEB-02"); INSERT INTO person VALUES ("GA", "Chase", "At", "01-FEB-02")
ERROR at line 1: ORA-00001: unique constraint (sqle.PERSON_UNIQUE) violated
SQL> INSERT INTO person VALUES ("BB", "Bob", "Bark", "28-FEB-02"); 1 row created. SQL> INSERT INTO person VALUES ("LB", "Laren", "Baby", "01-MAR-02"); 1 row created. SQL> INSERT INTO person VALUES ("LN", "Linda", "Norman", "01-JUN-03"); 1 row created. SQL> SQL> select * from person; PER FIRST_NAME LAST_NAME HIRE_DATE --- --------------- -------------------- --------- CA Chase At 01-FEB-02 BB Bob Bark 28-FEB-02 LB Laren Baby 01-MAR-02 LN Linda Norman 01-JUN-03 SQL> SQL> drop table person; Table dropped. SQL> SQL></source>
