в 13:45, 26 мая 2010

2010-05-26T13:45:46Z

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2010-05-26T10:05:04Z

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== 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>

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Admin: 1 версия