I have the below script , i want to modify it such a way lets say if it is executed first time then it will create the column but lets say if it is executed second time then it will show fail message which is not correct it should show the message that column is created and also if there comes any exception lets say column i s not created due to some technical exception then it should show fail message , please advise how to achieve this
SELECT COUNT(*) INTO L_COL_EXISTS FROM USER_TAB_COLS WHERE COLUMN_NAME = 'TOR' and TABLE_NAME='AVOICE';
IF L_COL_EXISTS = 1
THEN
outcome := 'Success';
ELSE
outcome := 'Fail';
END IF;
DBMS_OUTPUT.PUT_LINE(outcome);
folks please advise
I suppose it can help you
CREATE OR REPLACE PROCEDURE add_column
(
v_table_name IN VARCHAR2,
v_column_name IN VARCHAR2,
v_column_type IN VARCHAR2
)
IS
v_column_exists pls_integer;
v_ddl_str varchar2(1024);
BEGIN
BEGIN
SELECT count(*)
INTO v_column_exists
FROM user_tab_columns
WHERE table_name = upper(v_table_name)
and column_name = upper(v_column_name);
EXCEPTION
WHEN OTHERS THEN
RAISE;
END;
if v_column_exists = 0 then
v_ddl_str := 'alter table ' || v_table_name || ' add ( ' || v_column_name || ' ' || v_column_type || ')';
BEGIN
EXECUTE IMMEDIATE alter_str;
EXCEPTION
WHEN OTHERS THEN
dbms_output.put_line ('something wrong');
RAISE;
END;
ELSE
dbms_output.put_line ('Column exists');
END IF;
EXCEPTION
WHEN OTHERS THEN
RAISE;
END add_column;
/
Related
I have a table which contains the metadata of the table. The task is to periodically delete a specific set of tables, provided the information for where condition and how many days the data is retained are present.If a user needs to delete a data on daily basis, he simply enter his table name in audit log. The procedure will do the rest. The example is shown below.
Table structure:
CREATE TABLE delete_tbl_list (
id NUMBER NOT NULL,
table_name VARCHAR2(100) NOT NULL,
column_name VARCHAR2(100) NOT NULL,
day_retented NUMBER NOT NULL,
where_clause VARCHAR2(2000)
);
the day_retended is the number which will tell on how many days the data can hold.
select * from delete_tbl_list
ID TABLE_NAME COLUMN_NAME DAY_RETENTED WHERE_CLAUSE
---------- -----------------------------------------------
1 audit_log log_TS 60
So if i need to delete a table taking log_ts(timestamp) as column with 60days period as retention. The table in query needs to do
delete * from audit_log where log_ts<systimestamp -60
Now i need to do it using bulk delete and more dynamic and hence i wrote the procedure below,
create procedure dynamic_mass_delete as
TYPE tbl_rec_rowid IS TABLE OF ROWID INDEX BY PLS_INTEGER;
lv_del_exec_rec tbl_rec_rowid;
v_limit PLS_INTEGER := 10000;
m_date date:=sysdate;
total_records_deleted number:=0;
l_where delete_tbl_list.where_clause%type;
l_sql varchar2(2000);
TYPE ref_cur_type IS REF CURSOR;
delete_content ref_cur_type;
BEGIN
for i in (select table_name,COLUMN_NAME,DAY_RETENTED,WHERE_CLAUSE from delete_tbl_list) loop
DBMS_OUTPUT.PUT_LINE('tablename..'||i.table_name);
l_where:='';
m_date:=m_date-i.day_retented;
if i.where_clause is not null then
l_where:=' and '||i.where_clause;
end if;
OPEN delete_content FOR 'SELECT rowid from ' || i.table_name ||' where '|| i.COLUMN_NAME || ' <= to_timestamp('''||m_date||''')'||l_where;
LOOP
total_records_deleted := 0;
FETCH delete_content BULK COLLECT INTO lv_del_exec_rec LIMIT v_limit;
FORALL j IN lv_del_exec_rec.first..lv_del_exec_rec.last
execute immediate 'DELETE FROM :1 where rowid=:2 'using i.table_name,lv_del_exec_rec(j);
total_records_deleted := total_records_deleted + SQL%rowcount;
DBMS_OUTPUT.PUT_LINE('Delete count..'||total_records_deleted);
EXIT WHEN delete_content%notfound;
END LOOP;
CLOSE delete_content;
end loop;
EXCEPTION
when others then
DBMS_OUTPUT.PUT_LINE('Error-->'||SQLERRM);
END;
/
Now i getting error in the delete query stating invalid table name, i was not able to write dbms_output inside for all statment. Is it possible to use multiple bind variable inside a pl/sql procedure.
The error which i get is ,
Error-->ORA-00942: table or view does not exist
PL/SQL procedure successfully completed.
The table very much exists, but it is throwing error, i was not able to print inside the forall block too.
Switch to
execute immediate 'DELETE FROM ' || i.table_name ||' where rowid = ' || lv_del_exec_rec(j);
You can simplify your code as follows:
BEGIN
FOR TBL_DETAILS IN (
SELECT
TABLE_NAME,
COLUMN_NAME,
DAY_RETENTED,
WHERE_CLAUSE
FROM
DELETE_TBL_LIST
) LOOP
DBMS_OUTPUT.PUT_LINE('tablename..' || TBL_DETAILS.TABLE_NAME);
EXECUTE IMMEDIATE 'DELETE FROM '
|| TBL_DETAILS.TABLE_NAME
|| ' WHERE '
|| TBL_DETAILS.COLUMN_NAME
|| ' < SYSTIMESTAMP - '
|| TBL_DETAILS.DAY_RETENTED
|| CASE
WHEN TBL_DETAILS.WHERE_CLAUSE IS NOT NULL THEN ' AND ' || TBL_DETAILS.WHERE_CLAUSE
END;
DBMS_OUTPUT.PUT_LINE('Delete count..' || SQL%ROWCOUNT);
END LOOP;
END;
/
Hope, This will help you in creating simpler code.
Cheers!!
I have declared the following procedure:
CREATE OR REPLACE PROCEDURE MODIFY_NOT_NULL(
v_tbName IN VARCHAR2,
v_cName IN VARCHAR2,
v_defaultValue IN VARCHAR2 )
IS
v_is_null VARCHAR2(1);
BEGIN
SELECT nullable INTO v_is_null
FROM USER_TAB_COLUMNS
WHERE TABLE_NAME = v_tbName
AND COLUMN_NAME = v_cName;
IF v_is_null = 'Y' THEN
EXECUTE IMMEDIATE ('ALTER TABLE ' || v_tbName
|| ' MODIFY (' || v_cName
|| ' DEFAULT ' || v_defaultValue
|| ' NOT NULL )');
END IF;
END;
However when I execute my code:
BEGIN
modify_not_null('TABLE_NAME', 'COLUMN_NAME ' ,'0');
END;
/
I am getting a
"ORA-01403: No Data Found"
This exception will be usually thrown if the "SELECT INTO" statement does not return any value, however I will always get a value when I execute this:
Select nullable
from USER_TAB_COLUMNS
WHERE table_name = 'TABLE_NAME'
AND column_name = 'COLUMN_NAME';
When I execute the code above, I get "N" or "Y" as a result. So I always get a result. I don't know why this exception is thrown
Your call contains a trailing space:
modify_not_null('TABLE_NAME', 'COLUMN_NAME ' ,'0');
^
So proc throws no data found because 'COLUMN_NAME ' != 'COLUMN_NAME'
Use upper(trim(v_cName)) to prevent typos causing errors. Apply on all parameters.
You are passing v_defaultValue param to column name.
Change procedure to
SELECT nullable INTO v_is_null
FROM USER_TAB_COLUMNS
WHERE TABLE_NAME = v_tbName AND COLUMN_NAME = v_cName ;
Before your SELECT .... INTO, you have to make sure that there is something to select. Because depending on what user you are, and what parameters you give, there may be no data in your table.
A simple way would be to have a COUNT at the beginning before the SELECT:
CREATE OR REPLACE PROCEDURE MODIFY_NOT_NULL(
v_tbName IN VARCHAR2,
v_cName IN VARCHAR2,
v_defaultValue IN VARCHAR2 )
IS
v_is_null VARCHAR2(1);
v_count number;
BEGIN
-- added select count
SELECT count(1) INTO v_count FROM USER_TAB_COLUMNS WHERE TABLE_NAME = trim(v_tbName) AND COLUMN_NAME = trim(v_cName);
-- added if v_count=1
if v_count = 1 then
SELECT nullable INTO v_is_null FROM USER_TAB_COLUMNS WHERE TABLE_NAME = trim(v_tbName) AND COLUMN_NAME = trim(v_cName);
IF v_is_null = 'Y' THEN
EXECUTE IMMEDIATE ('ALTER TABLE ' || v_tbName || ' MODIFY (' || v_cName || ' DEFAULT ' || v_defaultValue || ' NOT NULL )');
END IF;
-- added
end if;
END;
/
Share and enjoy
stay classy :)
create or replace procedure modify_not_null(v_tbName in varchar2,
v_cName in varchar2,
v_defaultValue in varchar2) is
cursor c_tbl(cp_tbname in varchar2,
cp_cname in varchar2) is
select nullable
from user_tab_columns
where table_name = upper(cp_tbname)
and column_name = upper(cp_cname);
l_tbl c_tbl%rowtype;
begin
open c_tbl(cp_tbname => v_tbName,
cp_cname => v_cName);
fetch c_tbl into l_tbl;
close c_tbl;
if l_tbl.nullable = 'Y' then
execute immediate 'alter table ' || v_tbName || ' modify (' || v_cName ||
' default ' || v_defaultValue || ' not null )';
end if;
exception
when others then
raise_application_error(-20000, dbms_utility.format_error_stack);
end modify_not_null;
I was trying to create a PL/SQL program to search for a value in entire database. Following is the code:
DECLARE
custom_query VARCHAR2(100);
user_input VARCHAR2(100);
i NUMBER (6);
TYPE temp_record
IS
varray(1000) OF VARCHAR2(100);
CURSOR t_rec IS
SELECT a.name AS t_name,
b.name AS c_name
FROM sys.TABLES a,
sys.COLUMNS b
WHERE a.object_id = b.object_id;
table_rec t_name%ROWTYPE;
BEGIN
IF NOT t_rec%isopen THEN
OPEN t_rec;
END IF;
FETCH t_rec
INTO table_rec;
WHILE t_rec%FOUND THEN
LOOP
custom_query := 'select'
|| table_rec.c_name
|| 'into temp_record from'
||table_rec.t_name ;
dbms_output.Put_line(custom_query);
EXECUTE IMMEDIATE custom_query;
FOR i IN 1 .. temp_record.count
LOOP
IF (Temp_record(i) = user_input) THEN
dbms_output.Put_line ('The value you are looking for is in '
|| table_rec.c_name
|| 'column of table'
|| table_rec.t_name);
END IF;
END LOOP;
END LOOP;
END;
Can anyone let me know what's wrong with this code?
Use ALL_TAB_COLUMNS to iterate all tables and columns in your dynamic query.
I need to drop an Oracle table only if it 1) exists AND 2) Is NOT Empty
I wrote this code but if the table does not exist the code does not work:
DECLARE
rec_cnt1 NUMBER :=0;
rec_cnt2 NUMBER :=0;
BEGIN
SELECT COUNT(*) INTO rec_cnt1 FROM ALL_TABLES WHERE TABLE_NAME = 'MyTable';
SELECT num_rows INTO rec_cnt2 FROM USER_TABLES WHERE TABLE_NAME = 'MyTable';
IF rec_cnt1 = 1 THEN
BEGIN
IF rec_cnt2 < 1 THEN
EXECUTE IMMEDIATE 'DROP TABLE MyTable cascade constraints';
END IF;
END;
END IF;
END;
/
What am I doing wrong? Please help.
Many thanks in advance
If you want to drop a table if it exists and empty(as the title of the question states) you could do this as follows:
create or replace procedure DropTableIfEmpty(p_tab_name varchar2)
is
l_tab_not_exists exception;
pragma exception_init(l_tab_not_exists, -942);
l_is_empty number;
l_query varchar2(1000);
l_table_name varchar2(32);
begin
l_table_name := dbms_assert.simple_sql_name(p_tab_name);
l_query := 'select count(*)
from ' || l_table_name ||
' where rownum = 1';
execute immediate l_query
into l_is_empty;
if l_is_empty = 0
then
execute immediate 'drop table ' || l_table_name;
dbms_output.put_line('Table "'|| p_tab_name ||'" has been dropped');
else
dbms_output.put_line('Table "'|| p_tab_name ||'" exists and is not empty');
end if;
exception
when l_tab_not_exists
then dbms_output.put_line('Table "'|| p_tab_name ||'" does not exist');
end;
When you are trying to drop a table, or query a table, which does not exist, Oracle will raise ORA-00942 exception and execution of a pl/sql block halts. We use pragma exception_init statement to associate ORA-00942 exception with our locally defined exception l_tab_not_exists in order to handle it appropriately.
Test case:
SQL> exec droptableifempty('tb_test'); -- tb_test table does not exists
Table "tb_test" does not exist
SQL> create table tb_test(
2 col number
3 );
table TB_TEST created.
SQL> exec droptableifempty('tb_test');
Table "tb_test" has been dropped
As a side note. Before querying num_rows column of [dba][all][user]_tables in order to determine number of rows a table has, you need to gather table statistic by executing dbms_stats.gather_table_stats(user, '<<table_name>>');, otherwise you wont get the actual number of rows.
In PL/SQL it is 'normal' to catch the exception.
If it is the correct exception then continue with the next part of your code.
DECLARE
rec_cnt1 NUMBER :=0;
rec_cnt2 NUMBER :=0;
BEGIN
SELECT COUNT(*) INTO rec_cnt1 FROM ALL_TABLES WHERE TABLE_NAME = 'MyTable';
SELECT num_rows INTO rec_cnt2 FROM USER_TABLES WHERE TABLE_NAME = 'MyTable';
IF rec_cnt1 = 1 THEN
BEGIN
IF rec_cnt2 < 1 THEN
EXECUTE IMMEDIATE 'DROP TABLE MyTable cascade constraints';
END IF;
END;
END IF;
EXCEPTION
DBMS_OUTPUT.PUT_LINE('OH DEAR AN EXCEPTION WAS THROWN DUE TO' || SQLERRM);
DBMS_OUTPUT.PUT_LINE('THE ORACLE CODE IS ' || SQLCODE);
-- if it is the oracle code for no such table, or no data selected
-- everything is fine.
END;
Of course it won't work if the table doesn't exist. Your second select would get a "No data found" exception, and you're not doing any exception handling. At least you should move the second select inside the first IF block. Best to add exception handling.
here is an easy way to solve this problem:
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE [sssss]';
EXCEPTION WHEN OTHERS THEN NULL;
END;
In the below PL/SQL code, TABLE_ONE holds table name tname , column name cname and rowid rid. The For loop fetches records from TABLE_ONE and updates column cname in table tname for the record with row id rid. But if the record to be updated in tname is locked then the for loop gets stuck and no further records from TABLE_ONE are processed. Ideally, the script to ignore the records for which update failed and proceed further. Please advise what could be the issue.
BEGIN
FOR c IN (SELECT * FROM TABLE_ONE a )
LOOP
DECLARE
TNAME varchar2(30);
CNAME varchar2(30);
RID ROWID;
X number;
updt_stmt varchar2(300);
BEGIN
BEGIN
TNAME := c.TNAME;
CNAME := c.CNAME;
RID := c.RID;
DBMS_OUTPUT.PUT_LINE( TNAME || '=>' || CNAME);
updt_stmt := 'UPDATE ' || TNAME || ' SET ' || CNAME || ' = ''123'' WHERE ROWID like ''%' || RID || '%''';
EXECUTE IMMEDIATE updt_stmt;
EXCEPTION
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE('ERROR');
END;
END;
END LOOP;
END;
Untested, but I think you could first try to lock the record with FOR UPDATE and by specifying NOWAIT cause a failure if some other transaction was active. You could then catch this exception and skip processing. Here is an untested example:
DECLARE
x ROWID;
resource_busy EXCEPTION;
PRAGMA EXCEPTION_INIT(resource_busy,
-00054);
BEGIN
FOR c IN (SELECT *
FROM table_one a)
LOOP
DECLARE
tname VARCHAR2(30);
cname VARCHAR2(30);
rid ROWID;
x NUMBER;
updt_stmt VARCHAR2(300);
BEGIN
BEGIN
tname := c.tname;
cname := c.cname;
rid := c.rid;
dbms_output.put_line(tname || '=>' || cname);
BEGIN
EXECUTE IMMEDIATE 'SELECT rowid FROM ' || tname ||
' WHERE rowid = :x FOR UPDATE NOWAIT'
INTO x
USING rid;
EXCEPTION
WHEN resource_busy THEN
dbms_output.put_line('Record locked; try again later.');
CONTINUE;
END;
updt_stmt := 'UPDATE ' || tname || ' SET ' || cname ||
' = ''123'' WHERE ROWID like ''%' || rid || '%''';
EXECUTE IMMEDIATE updt_stmt;
EXCEPTION
WHEN OTHERS THEN
dbms_output.put_line('ERROR');
END;
END;
END LOOP;
END;