Oracle PL/SQL/Constraints/Add Constraint — различия между версиями

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Текущая версия на 10:02, 26 мая 2010

Adding constraints to a table: not null

 
SQL> -- create demo table
SQL> create table Employee(
  2    ID                 VARCHAR2(4 BYTE)         NOT NULL,
  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>
SQL>
SQL> --Adding constraints to a table
SQL>
SQL> ALTER TABLE Employee MODIFY (Start_Date Date NOT NULL);
Table altered.
SQL>
SQL> SELECT constraint_name, constraint_type,
  2      search_condition
  3      FROM USER_CONSTRAINTS
  4      WHERE table_name ="EMPLOYEE";
CONSTRAINT_NAME                C SEARCH_CONDITION
------------------------------ - --------------------------------------------------------------------------------
SYS_C004882                    C "ID" IS NOT NULL
SYS_C004883                    C "START_DATE" IS NOT NULL
SQL>
SQL> -- clean the table
SQL> drop table Employee
  2  /
Table dropped.
SQL>
SQL>
SQL>



Alter table to add constraint with name

 
SQL> --Unique Key
SQL>
SQL>
SQL> create table myTable (
  2    a number unique,
  3    b number
  4  );
Table created.
SQL>
SQL>
SQL> alter table myTable add constraint uq_ri_b unique (b);
Table altered.
SQL>
SQL>
SQL> insert into myTable values (4,   5);
1 row created.
SQL> insert into myTable values (2,   1);
1 row created.
SQL> insert into myTable values (2,   1); -- Dup
  2  insert into myTable values (9,   8);
insert into myTable values (2,   1); -- Dup
                                   *
ERROR at line 1:
ORA-00911: invalid character

SQL> insert into myTable values (6,   9);
1 row created.
SQL> insert into myTable values (null,9);
insert into myTable values (null,9)
*
ERROR at line 1:
ORA-00001: unique constraint (SYS.UQ_RI_B) violated

SQL> insert into myTable values (null,9);
insert into myTable values (null,9)
*
ERROR at line 1:
ORA-00001: unique constraint (SYS.UQ_RI_B) violated

SQL>
SQL> select * from myTable;
         A          B
---------- ----------
         4          5
         2          1
         6          9
SQL>
SQL> drop table myTable;
Table dropped.
SQL>
SQL>



Naming contraints

    
SQL> create table salary
  2  ( grade      NUMBER(2)   constraint S_PK primary key
  3  , lowerlimit NUMBER(6,2) constraint S_LOWER_NN
  4                           not null
  5                           constraint S_LOWER_CHK
  6                           check (lowerlimit >= 0)
  7  , upperlimit NUMBER(6,2) constraint S_UPPER_NN
  8                           not null
  9  , bonus      NUMBER(6,2) constraint S_BONUS_NN
 10                           not null
 11  , constraint S_LO_UP_CHK check
 12                           (lowerlimit <= upperlimit)
 13  ) ;
Table created.
SQL>
SQL>
SQL> drop table salary;
Table dropped.



Salary column value cannot be greater than 1000

    
SQL>
SQL>
SQL> create table emp(
  2    EmpNo            NUMBER(10)    PRIMARY KEY,
  3    Name             VARCHAR2(40)  NOT NULL,
  4    DeptNo           NUMBER(2)     DEFAULT NULL,
  5    Salary           NUMBER(7,2)   CHECK (salary < 1000),
  6    Birth_Date       DATE,
  7    Soc_Sec_Num      CHAR(9)       UNIQUE);
Table created.
SQL>
SQL>
SQL>
SQL>
SQL> drop table emp;
Table dropped.
SQL>
SQL>