I would like to rename a constraint, in oracle database, without specify it's name, but with selecting it's name. I would like to do something like this:
ALTER TABLE O4Y_USER RENAME CONSTRAINT
(SELECT constraint_name
FROM user_constraints
WHERE table_name = 'O4Y_USER'
AND constraint_type = 'P'
) TO 'O4Y_USER_PK';
It is not working, I have the following error
The select alone, is working well, it returns the correct value. How is the correct syntax to do, to work the alter statement?
You can use dynamic SQL. Something like:
DECLARE
p_constraint_name VARCHAR2(30);
p_sql VARCHAR2(4000);
BEGIN
SELECT constraint_name
INTO p_constraint_name
FROM user_constraints
WHERE table_name = 'O4Y_USER'
AND constraint_type = 'P';
p_sql := 'ALTER TABLE O4Y_USER RENAME CONSTRAINT "'
|| p_constraint_name
|| '" TO ''O4Y_USER_PK''';
DBMS_OUTPUT.PUT_LINE( p_sql );
EXECUTE IMMEDIATE p_sql;
EXCEPTION
WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE( 'Constraint not found!' );
END;
/
And just the same method using SQL*Plus or similar command line tools.
SQL> create table t ( x int primary key );
Table created.
SQL>
SQL> col cname new_value x
SQL>
SQL> SELECT constraint_name cname
2 FROM user_constraints
3 WHERE table_name = 'T'
4 AND constraint_type = 'P';
CNAME
----------------------------------------------------------------------
SYS_C0068724
SQL>
SQL> ALTER TABLE t RENAME CONSTRAINT &&x to my_new_name;
old 1: ALTER TABLE t RENAME CONSTRAINT &&x to my_new_name
new 1: ALTER TABLE t RENAME CONSTRAINT SYS_C0068724 to my_new_name
Table altered.
Related
I am trying to get the name of a constraint and then alter a table to remove the constraint. The constraint has not been named so I guess I have no other option. Here is what I tried:
DECLARE
the_variable VARCHAR2(20);
BEGIN
SELECT CONSTRAINT_NAME INTO the_variable
FROM all_constraints
WHERE table_name = 'MY_TABLE'
AND SEARCH_CONDITION_VC = 'format IN (''CSV'', ''PDF'')';
END;
The query above seems to work fine, but when I try to alter the table in this way:
ALTER TABLE SOME_TABLE DROP CONSTRAINT the_variable;
I get this error:
SQL Error [6550] [65000]: ORA-06550: line 14, column 1:
PLS-00103: Encountered the symbol "ALTER"
You can't perform DDL like that; has to be dynamic SQL. Here's an example - you need what's written in line #9:
SQL> create table my_table (id number primary key);
Table created.
SQL> declare
2 the_variable varchar2(30);
3 begin
4 select constraint_name
5 into the_variable
6 from all_constraints
7 where table_name = 'MY_TABLE';
8
9 execute immediate 'alter table my_table drop constraint ' || the_variable;
10 end;
11 /
PL/SQL procedure successfully completed.
SQL> select count(*) from all_constraints where table_name = 'MY_TABLE';
COUNT(*)
----------
0
SQL>
I am new to Oracle, I am trying to write a procedure in Oracle to delete foreign key constraints for a table. I have already done this for MySQL and its working. I am not sure with the syntax, apologies for that, but my query is working If I run it individually. I want to do the same thing(removing foreign key constraints) for multiple tables and don't want to write queries multiple times. hence first I am finding the foreign keys associated with that table , storing them in cursor and later removing all of the foreign keys by creating and executing drop constraints query associated with that table. following code is giving multiple errors to me.
CREATE OR REPLACE PROCEDURE removeConstraintsForTable(vTableName IN varchar2) IS
BEGIN
cName VARCHAR(2048);
sql_stmt VARCHAR2(2048);
CURSOR cur IS
SELECT DISTINCT CONSTRAINT_NAME
FROM ALL_CONSTRAINTS WHERE OWNER= sys_context('userenv','current_schema')
AND TABLE_NAME = vTableName AND CONSTRAINT_TYPE='R';
BEGIN
OPEN cur;
LOOP
FETCH cur INTO cName;
EXIT WHEN cur%notfound;
sql_stmt := CONCAT(CONCAT(CONCAT('ALTER TABLE ',vTableName),CONCAT(' DROP FOREIGN KEY ',cName)),';');
SELECT sql_stmt FROM dual;
INSERT INTO TEMP(Name) VALUES(sql_stmt);
COMMIT;
END LOOP;
END
/
CALL removeConstraintsForTable('table1');
CALL removeConstraintsForTable('table2');
CALL removeConstraintsForTable('table3');
CALL removeConstraintsForTable('table4');
COMMIT;
You have an extra BEGIN right at the start of your procedure, and the final END is missing a semicolon. You shouldn't really be using VARCHAR, and you could declare the cName variable using the data dictionary anyway; however an implicit loop will be simpler, as will using the concatenation operator || instead of nested CONCAT() calls, and the generated statement should not end in a semicolon:
create or replace procedure removeconstraintsfortable(p_table_name in varchar2) is
sql_stmt varchar2(2048);
begin
for rec in (
select owner, constraint_name
from all_constraints
where owner = sys_context('userenv','current_schema')
and table_name = p_table_name
and constraint_type = 'R'
)
loop
sql_stmt := 'ALTER TABLE "' || rec.owner || '"."' || p_table_name || '"'
|| ' DROP CONSTRAINT "' || rec.constraint_name || '"';
insert into temp(name) values(sql_stmt);
end loop;
commit;
end;
/
As pointed out in comments, the generated statement should be drop constraint.
I'm not sure why you're inserting into a table or where you execute the statement, but you can do it all in one if you prefer:
create or replace procedure removeconstraintsfortable(p_table_name in varchar2) is
sql_stmt varchar2(2048);
begin
for rec in (
select owner, constraint_name
from all_constraints
where owner = sys_context('userenv','current_schema')
and table_name = p_table_name
and constraint_type = 'R'
)
loop
sql_stmt := 'ALTER TABLE "' || rec.owner || '"."' || p_table_name || '"'
|| ' DROP CONSTRAINT "' || rec.constraint_name || '"';
dbms_output.put_line(sql_stmt);
execute immediate sql_stmt;
end loop;
end;
/
The dbms_output call just shows you the generated statement(s), before execute immediate executes it, well, immediately.
Quick demo; very basic table set-up:
create table t42 (id number primary key);
create table t43 (id number references t42 (id));
select table_name, constraint_name, constraint_type
from all_constraints
where table_name in ('T42', 'T43');
TABLE_NAME CONSTRAINT_NAME C
------------------------------ ------------------------------ -
T43 SYS_C00138153 R
T42 SYS_C00138152 P
Then call the procedure which shows the generated statement:
set serveroutput on
exec removeConstraintsForTable('T43');
ALTER TABLE "STACKOVERFLOW"."T43" DROP CONSTRAINT "SYS_C00138153"
PL/SQL procedure successfully completed.
and then check the constraint has gone:
select table_name, constraint_name, constraint_type
from all_constraints
where table_name in ('T42', 'T43');
TABLE_NAME CONSTRAINT_NAME C
------------------------------ ------------------------------ -
T42 SYS_C00138152 P
I fixed a number of syntax issues for you. Try this.
CREATE OR REPLACE PROCEDURE removeConstraintsForTable(vTableName IN varchar2) IS
cName VARCHAR2(30); -- identifiers are max 30 chars
sql_stmt VARCHAR2(2048);
CURSOR cur IS
SELECT DISTINCT CONSTRAINT_NAME
FROM USER_CONSTRAINTS
WHERE TABLE_NAME = vTableName AND CONSTRAINT_TYPE='R';
BEGIN
OPEN cur;
LOOP
FETCH cur INTO cName;
EXIT WHEN cur%notfound;
sql_stmt := 'ALTER TABLE ' || vTableName || ' DROP CONSTRAINT ' || cName;
INSERT INTO RANGERADMIN1.TEMP(Name) VALUES(sql_stmt);
END LOOP;
COMMIT;
END removeConstraintsForTable;
/
call removeConstraintsForTable('table1');
call removeConstraintsForTable('table2');
call removeConstraintsForTable('table3');
call removeConstraintsForTable('table4');
-- COMMIT; -- not necessary
I create a table in oracle 12 with a column as identity. The problem is that I want to find the current value of identity column. How I can find this, please someone help me to solve this problem...
You could make use of the data dictionary views *_TAB_IDENTITY_COLS
Here is a working example.
create TABLE t ( ID INTEGER GENERATED BY DEFAULT AS IDENTITY, NAME VARCHAR2(10));
Table created.
INSERT INTO t(NAME) VALUES ( 'TESTER' );
1 row(s) inserted.
select SEQUENCE_NAME FROM user_tab_identity_cols WHERE TABLE_NAME ='T' ;
SEQUENCE_NAME
-----------
ISEQ$$_1727054
Now you could get the currval from this sequence.
select ISEQ$$_1727054.CURRVAL FROM DUAL;
CURRVAL
-------
1
LIVESQL DEMO - Free OTN account required.
Why do you want to know? If to insert a child row you can use the returning clause of the insert statement like this:
insert into master (...) values (...)
returning master_id into l_master_id;
insert into child (master_id, ...) values (l_master_id, ...);
As I've written in this blog post, this query produces all the identities' backing sequences' currval values of your schema:
with
function current_value(p_table_name varchar2) return number is
v_current number;
begin
for rec in (
select data_default
from user_tab_cols
where table_name = p_table_name
and data_default is not null
and identity_column = 'YES'
)
loop
execute immediate replace(
'select ' || rec.data_default || ' from dual',
'.nextval',
'.currval'
) into v_current;
return v_current;
end loop;
return null;
end;
select *
from (
select table_name, current_value(table_name) current_value
from user_tables
)
where current_value is not null
order by table_name;
/
The output could be something like this:
TABLE_NAME CURRENT_VALUE
--------------------------
T1 3
T2 1
I get following error when I am attempting to disable constraints from hr.employees table
Error:
Error report -
ORA-02250: missing or invalid constraint name
ORA-06512: at line 14
02250. 00000 - "missing or invalid constraint name"
*Cause: The constraint name is missing or invalid.
*Action: Specify a valid identifier name for the constraint name.
Following is the code
DECLARE
CURSOR C1 IS SELECT CONSTRAINT_NAME FROM USER_CONSTRAINTS WHERE TABLE_NAME ='EMPLOYEES';
v_con_name VARCHAR2(20);
SQL_STATMENT VARCHAR2(100);
BEGIN
SQL_STATMENT := 'ALTER TABLE HR.EMPLOYEES DISABLE CONSTRAINT :A';
OPEN C1;
LOOP
FETCH C1 INTO v_con_name;
EXIT WHEN C1%NOTFOUND;
EXECUTE IMMEDIATE SQL_STATMENT USING v_con_name;
DBMS_OUTPUT.PUT_LINE(v_con_name);
END LOOP;
CLOSE C1;
END;
/
When I comment following line
EXECUTE IMMEDIATE SQL_STATMENT USING v_con_name;
Scripts execute successfully and provide following results
EMP_LAST_NAME_NN
EMP_EMAIL_NN
EMP_HIRE_DATE_NN
EMP_JOB_NN
EMP_SALARY_MIN
EMP_EMAIL_UK
EMP_EMP_ID_PK
EMP_DEPT_FK
EMP_JOB_FK
EMP_MANAGER_FK
PL/SQL procedure successfully completed.
Hence I understand that the cursor construct is fetching the desired constraints name and also outside of this plsql block, I could successfully alter employees table by disabling these constraints.
Please note that I have logged in as HR schema in Oracle 11g R2 XE database
I am not sure why I am getting the missing or invalid constraint name.. thanks to help me here.
You can't use bind variables for the names of database objects (or for DDL in general). You will need to build the entire ALTER statement by concatenating the name. Try something like this:
declare
k_tablename constant user_constraints.table_name%type := 'EMPLOYEES';
begin
for r in (
select constraint_name
, 'alter table ' || c.table_name || ' disable constraint ' || c.constraint_name as sql_statement
from user_constraints c
where table_name = k_tablename
)
loop
execute immediate r.sql_statement;
dbms_output.put_line('Disabled constraint ' || k_tablename || '.' || r.constraint_name);
end loop;
end;
/
Why don't you use this script to generate the DISABLE script?
SELECT 'ALTER TABLE '||OWNER||'.'||TABLE_NAME||' DISABLE CONSTRAINT '||CONSTRAINT_NAME||';' STMNT
FROM DBA_CONSTRAINTS
WHERE
R_CONSTRAINT_NAME IN
(SELECT CONSTRAINT_NAME
FROM DBA_CONSTRAINTS
WHERE CONSTRAINT_TYPE IN ('P','U')
AND OWNER = 'HR'
AND TABLE_NAME IN
(
'EMPLOYEES'
));
Somewhat simpler (& working) then the original attempt:
SQL> create table test (id number constraint pk_test primary key,
2 ime varchar2(20) constraint ch_ime check (ime in ('little', 'foot')));
Table created.
SQL>
SQL> begin
2 for c1 in (select table_name, constraint_name
3 from user_constraints
4 where table_name = 'TEST')
5 loop
6 execute immediate 'alter table ' || c1.table_name ||
7 ' disable constraint ' || c1.constraint_name;
8 end loop;
9 end;
10 /
PL/SQL procedure successfully completed.
SQL> select constraint_name, status From user_constraints where table_name = 'TEST';
CONSTRAINT_NAME STATUS
------------------------------ --------
CH_IME DISABLED
PK_TEST DISABLED
SQL>
Using Oracle 10g, I need to rename a bunch of FK constraints which all end in LITE to include an FK prefix.
My thinking was (I've ensured all names are short enough to accommodate the prefix):
DECLARE
v_name VARCHAR2(30 BYTE);
v_new_name VARCHAR2(30 BYTE);
CURSOR c1 is select CONSTRAINT name from user_constraints where constraint_type = 'R' and constraint_name like '%_LITE';
BEGIN
OPEN c1;
LOOP
FETCH c1 into v_name;
EXIT when c1%NOTFOUND;
v_new_name:= 'FK_' || v_name;
update user_constraints SET constraint_name = v_new_name where constraint_name = v_name;
END LOOP;
close c1;
END;
Any reason why that would be unsafe and I should have to create alter table statements instead?
USER_CONSTRAINTS is a view, you cannot update it as a normal user. EDIT: Even SYS cannot do that, and doing updates on the data dictionary seems like an incredibly bad idea to me.
Better use ALTER TABLE xxx RENAME CONSTRAINT yyy TO zzz;
As ammoQ says, don't even think about doing that! This is the equivalent code using ALTER TABLE:
BEGIN
FOR r IN (select constraint_name
from user_constraints
where constraint_type = 'R'
and constraint_name like '%_LITE'
)
LOOP
EXECUTE IMMEDIATE 'ALTER TABLE ' || r.table_name
|| ' RENAME CONSTRAINT ' || r.constraint_name
|| ' TO FK_' ||v_new_name;
END LOOP;
END;