PLSQL - Drop all database objects of a user - oracle

I'm trying to use a procedure (no parameters) to drop all of the user-created database objects located within the schema from where the procedure is launched, but I'm really not sure on how to go about this. Here's what I have so far, but I think I'm going about this the wrong way.
create or replace procedure CLEAN_SCHEMA is
cursor schema_cur is
select 'drop '||object_type||' '|| object_name|| DECODE(OBJECT_TYPE,'TABLE',' CASCADE CONSTRAINTS;',';')
from user_objects;
schema_rec schema_cur%rowtype;
begin
select 'drop '||object_type||' '|| object_name|| DECODE(OBJECT_TYPE,'TABLE',' CASCADE CONSTRAINTS;',';')
into schema_rec
from user_objects;
end;
/

create or replace
FUNCTION DROP_ALL_SCHEMA_OBJECTS RETURN NUMBER AS
PRAGMA AUTONOMOUS_TRANSACTION;
cursor c_get_objects is
select object_type,'"'||object_name||'"'||decode(object_type,'TABLE' ,' cascade constraints',null) obj_name
from user_objects
where object_type in ('TABLE','VIEW','PACKAGE','SEQUENCE','SYNONYM', 'MATERIALIZED VIEW')
order by object_type;
cursor c_get_objects_type is
select object_type, '"'||object_name||'"' obj_name
from user_objects
where object_type in ('TYPE');
BEGIN
begin
for object_rec in c_get_objects loop
execute immediate ('drop '||object_rec.object_type||' ' ||object_rec.obj_name);
end loop;
for object_rec in c_get_objects_type loop
begin
execute immediate ('drop '||object_rec.object_type||' ' ||object_rec.obj_name);
end;
end loop;
end;
RETURN 0;
END DROP_ALL_SCHEMA_OBJECTS;
Create the above function (autonomous so DDL can be called via a function)
then you can just:
select DROP_ALL_SCHEMA_OBJECTS from dual;
when you want to drop all your objects, make sure you dont try to drop the proc your running (i dont care about the procs thats why i dont have procs or functions in the object_type list)
if you want to drop everything you need an anonymous block
but i needed to be able to do this from a tool that only allowed ansi sql (not plsql) hence a stored proc.
Enjoy.

declare
cursor ix is
select *
from user_objects
where object_type in ('TABLE', 'VIEW', 'FUNCTION', 'SEQUENCE');
begin
for x in ix loop
execute immediate('drop '||x.object_type||' '||x.object_name);
end loop;
end;

Unless the user has hard to reapply permissions, its probably easier to just drop the user and recreate them.

Thanks Martin Brambley,
I feel we can simplify your answer in the following way.
CREATE OR REPLACE
procedure DROP_ALL_SCHEMA_OBJECTS AS
PRAGMA AUTONOMOUS_TRANSACTION;
cursor c_get_objects is
select object_type,'"'||object_name||'"'||decode(object_type,'TABLE' ,' cascade constraints',null) obj_name
FROM USER_OBJECTS
where object_type in ('TABLE','VIEW','PACKAGE','SEQUENCE','SYNONYM', 'MATERIALIZED VIEW', 'TYPE')
order by object_type;
BEGIN
begin
for object_rec in c_get_objects loop
execute immediate ('drop '||object_rec.object_type||' ' ||object_rec.obj_name);
end loop;
end;
END DROP_ALL_SCHEMA_OBJECTS;
/
execute DROP_ALL_SCHEMA_OBJECTS;

What you've got is a good start.
Here is the rest:
You have a cursor AND a select statement. You only need the cursor.
Your next step is to call the drop statement using dynamic PLSQL. I'd use the EXECUTE IMMEDIATE statement. Its more elegant and preformance friendly to just select the name of the thing you're dropping and submit it as a bind variable to EXECUTE IMMEDIATE.
In order to drop the objects of the schema calling the method and not the schema owning the method you have to use "AUTHID CURRENT_USER". See the Oracle documentation for more info.
Other things to drop: packages, functions, procedures (the system will likely hang then timeout if you try to drop this method while its running), Java classes, triggers, views, types
Lastly, this is obviously a very dangerous method so you may want to consider putting it in a script instead of a stored procedure so it isn't left in the database for anyone to run.

You're close - as someone else has noted you need an "EXECUTE IMMEDIATE" for the statement. You should consider:
Instead of creating a procedure to do this, run this as an anonymous PL/SQL block so you don't have the issue of trying to drop a procedure that is running.
Add a test for object type of TABLE and for that case modify the drop statement to include the cascade option to handle tables that are "parents" of other tables via foreign key constraints. Remember that you'll probably be generating the cursor list in an order that doesn't consider dependencies that will block the drop.
Also on the subject of dependencies, it is probably best to drop tables first (add a DECODE in your cursor that assigns a lower numeric value to this object type and order the cursor select by this value). If you have Oracle objects of type TYPE that are used as column types in a table definition the table must be dropped first.
If you use Oracle Advanced Queuing the objects related to this MUST be dropped with the AQ package API calls. Although you can drop the Oracle-generated tables for queue support with a regular DROP TABLE, you will find yourself in the catch-22 position of then not being able to drop the related queues nor add them back. Up to version 10g at least you couldn't even drop the containing schema without putting the database in a special mode when this situation existed

Thanks Martin Brambley and Vijayan Srinivasan!
But Vijayan Srinivasan's version is not correct, because dependent objects of type 'TYPE' sometime generates errors during drop them:
ORA-02303: cannot drop or replace a type with type or table dependents
My version drop ALL objects from Schema with additional:
drop procedures and functions (expect 'DROP_ALL_SCHEMA_OBJECTS')
drop all jobs and dbms_jobs
drop all db_links
do not drop nested tables, because DROPing of nested tables not supported
CREATE OR REPLACE
procedure DROP_ALL_SCHEMA_OBJECTS AS
PRAGMA AUTONOMOUS_TRANSACTION;
cursor c_get_objects is
select uo.object_type object_type_2,'"'||uo.object_name||'"'||decode(uo.object_type,'TABLE' ,' cascade constraints',null) obj_name2
FROM USER_OBJECTS uo
where uo.object_type in ('TABLE','VIEW','PACKAGE','SEQUENCE','SYNONYM', 'MATERIALIZED VIEW', 'FUNCTION', 'PROCEDURE')
and not (uo.object_type = 'TABLE' and exists (select 1 from user_nested_tables unt where uo.object_name = unt.table_name))
and not (uo.object_type = 'PROCEDURE' and uo.object_name = 'DROP_ALL_SCHEMA_OBJECTS')
order by uo.object_type;
cursor c_get_objects_type is
select object_type, '"'||object_name||'"' obj_name
from user_objects
where object_type in ('TYPE');
cursor c_get_dblinks is
select '"'||db_link||'"' obj_name
from user_db_links;
cursor c_get_jobs is
select '"'||object_name||'"' obj_name
from user_objects
where object_type = 'JOB';
cursor c_get_dbms_jobs is
select job obj_number_id
from user_jobs
where schema_user != 'SYSMAN';
BEGIN
begin
for object_rec in c_get_objects loop
execute immediate ('drop '||object_rec.object_type_2||' ' ||object_rec.obj_name2);
end loop;
for object_rec in c_get_objects_type loop
begin
execute immediate ('drop '||object_rec.object_type||' ' ||object_rec.obj_name);
end;
end loop;
for object_rec in c_get_dblinks loop
execute immediate ('drop database link '||object_rec.obj_name);
end loop;
for object_rec in c_get_jobs loop
DBMS_SCHEDULER.DROP_JOB(job_name => object_rec.obj_name);
end loop;
commit;
for object_rec in c_get_dbms_jobs loop
dbms_job.remove(object_rec.obj_number_id);
end loop;
commit;
end;
END DROP_ALL_SCHEMA_OBJECTS;
/
execute DROP_ALL_SCHEMA_OBJECTS;
drop procedure DROP_ALL_SCHEMA_OBJECTS;
exit;

Related

How to delete sequences and procedures during logoff trigger?

Could you please help me in a unique situation I am in. I am receiving "ORA-30511: invalid DDL operation in system triggers" when dropping sequences and procedures during logoff trigger.
I need to delete tables, sequences and procedures of users before logoff event happens. I am writing the table details in DB_OBJECTS table upon create using a separate trigger. Below is my logoff trigger - could you please help me where I am doing wrong. Dropping tables is working fine in the below code. Only Dropping sequences and procedures is giving me "ORA-30511: invalid DDL operation in system triggers" error.
CREATE OR REPLACE TRIGGER DELETE_BEFORE_LOGOFF
BEFORE LOGOFF ON DATABASE
DECLARE
USER_ID NUMBER := SYS_CONTEXT('USERENV', 'SESSIONID');
BEGIN
FOR O IN (SELECT USER, OBJECT_NAME, OBJECT_TYPE
FROM DB_OBJECTS WHERE SID = USER_ID
AND USERNAME = USER AND SYSDATE > CREATED_DTTM) LOOP
IF O.OBJECT_TYPE = 'TABLE' THEN
EXECUTE IMMEDIATE 'DROP TABLE ' || O.USER || '.' || O.OBJECT_NAME || ' CASCADE CONSTRAINTS';
ELSIF O.OBJECT_TYPE = 'SEQUENCE' THEN
EXECUTE IMMEDIATE 'DROP SEQUENCE ' || O.USER || '.' || O.OBJECT_NAME;
ELSIF O.OBJECT_TYPE = 'PROCEDURE' THEN
EXECUTE IMMEDIATE 'DROP PROCEDURE ' || O.USER || '.' || O.OBJECT_NAME;
END IF;
END LOOP;
EXCEPTION WHEN NO_DATA_FOUND THEN NULL;
END;
/
That's a simple one.
Error code: ORA-30511
Description: invalid DDL operation in system triggers
Cause: An attempt was made to perform an invalid DDL operation in a system trigger. Most DDL operations currently are not supported in system triggers. The only currently supported DDL operations are table operations and ALTER/COMPILE operations.
Action: Remove invalid DDL operations in system triggers.
That's why only
Dropping tables is working fine
succeeded.
Therefore, you can't do that using trigger.
You asked (in a comment) how to drop these objects, then. Manually, as far as I can tell. Though, that's quite unusual - what if someone accidentally logs off? You'd drop everything they created. If you use that schema for educational purposes (for example, every student gets their own schema), then you could create a "clean-up" script you'd run once class is over. Something like this:
SET SERVEROUTPUT ON;
DECLARE
l_user VARCHAR2 (30) := 'SCOTT';
l_str VARCHAR2 (200);
BEGIN
IF USER = l_user
THEN
FOR cur_r IN (SELECT object_name, object_type
FROM user_objects
WHERE object_name NOT IN ('EMP',
'DEPT',
'BONUS',
'SALGRADE'))
LOOP
BEGIN
l_str :=
'drop '
|| cur_r.object_type
|| ' "'
|| cur_r.object_name
|| '"';
DBMS_OUTPUT.put_line (l_str);
EXECUTE IMMEDIATE l_str;
EXCEPTION
WHEN OTHERS
THEN
NULL;
END;
END LOOP;
END IF;
END;
/
PURGE RECYCLEBIN;
It is far from being perfect; I use it to clean up my Scott schema I use to answer questions on various sites so - once it becomes a mess, I run that PL/SQL code several times (because of possible foreign key constraint).
Other option is to keep a create user script(s) (along with all grant statements) and - once class is over - drop existing user and simply recreate it.
Or, if that user contains some pre-built tables, keep export file (I mean, result of data pump export) and import it after the user is dropped.
There are various options - I don't know whether I managed to guess correctly, but now you have something to think about.

Oracle pl sql dynamic using clause

I have a question about "dynamic using clause" in execute immediate statement. I need to set dynamically the "execute immediate statement" and the using clause as well. I don't know the table structure, but I know only the name of the table, and I need to do an operation update on it.
So I wrote a function (through user_tab_columns and user user_constraints tables) to set a variable with the update statement and the bind_variable but now I need to set the using clause with the list of variable.
Example:
CREATE TABLE table1
(
rec1 VARCHAR2(10 BYTE) NULL,
rec2 DATE NULL,
rec3 number(9) not null
);
declare
TYPE cur_type IS REF CURSOR;
cur cur_type;
table_list table1%ROWTYPE;
sqlstring varchar2(400);
begin
OPEN cur FOR sqlstring;
LOOP
FETCH cur INTO table_list;
EXIT WHEN cur%NOTFOUND;
sqlstring:=function1('table1');
-- that returns sqlstring:='update table1 set rec1=:1 , rec2=:2 , rec3=:3 where rec_id=:c4';
execute immediate sqlstring using table_list.rec1, table_list.rec2, table_list.rec3, table_list.rec_id;
END LOOP;
close cur;
end;
I need to implement dynamically the list of variables of the cursor table_list.
"execute immediate sqlstring using table_list.rec1, table_list.rec2, table_list.rec3, table_list.rec_id"
Does anybody know how to solve this problem?
Thanks a lot for your replies.
The problem is that I'm assuming I don't know the table's structure and so the list of variables of the cursor table_list table1%ROWTYPE.
So I can't explicit table_list.rec1, table_list.rec2 ... in the using clause.
If I use only table_list as variable
begin
OPEN cur FOR sqlstring;
LOOP
FETCH cur INTO table_list;
EXIT WHEN cur%NOTFOUND;
sqlstring:=function1('table1');
execute immediate sqlstring using table_list;
END LOOP;
close cur;
I got the error:" 00457 Expressions have to be of SQL types"
http://psoug.org/oraerror/PLS-00457.htm
Error Cause:
An expression of wrong type is in USING or dynamic RETURNING clause. In USING or dynamic RETURNING clause, an expression cannot be of non-SQL types such as BOOLEAN, INDEX TABLE, and record.
I need a way to retrive not only the values but also the list of variables of the cursor table_list first.
But maybe it's impossible and I have to find a work around.
If I will find something interesting I will post.
Thankyou.
Try to replace your execute immediate to full use of dbms_sql.
http://docs.oracle.com/cd/B28359_01/appdev.111/b28419/d_sql.htm#i996891
And usefull for you will be bind_array function from this package.
Use dynamic PL/SQL, unless you can re-factor the original statement and just plug the values into it.
declare
v_string constant varchar2(32767) := 'update test1 set a = :1, b = :2';
v_using_string varchar2(32767);
begin
--Create dynamic using string.
--For example, let's say you want to pass in the values "1" for each NUMBER column.
select listagg(1, ',') within group (order by null)
into v_using_string
from user_tab_columns
where table_name = 'TEST1'
and data_type = 'NUMBER';
--Execute the original dynamic SQL, adding the USING string.
execute immediate '
begin
execute immediate '''||v_string||''' using '||v_using_string||';
end;
';
end;
/
You can either use DBMS_SQL package:
open a cursor using dbms_sql.open_cursor
parse the statement using dbms_sql.parse
bind variables in a loop using dbms_sql.bind_variable
execute the statement using dbms_sql.execute
and finally close the cursor using dbms_sql.close_cursor
Or EXECUTE IMMEDIATE of anonymous PL/SQL block, which performs a dynamically created EXECUTE IMMEDIATE (this approach is not suitable for returning data). See Answer of #JonHeller.

FORALL+ EXECUTE IMMEDIATE + INSERT Into tbl SELECT

I have got stuck in below and getting syntax error - Please help.
Basically I am using a collection to store few department ids and then would like to use these department ids as a filter condition while inserting data into emp table in FORALL statement.
Below is sample code:
while compiling this code i am getting error, my requirement is to use INSERT INTO table select * from table and cannot avoid it so please suggest.
create or replace Procedure abc(dblink VARCHAR2)
CURSOR dept_id is select dept_ids from dept;
TYPE nt_dept_detail IS TABLE OF VARCHAR2(25);
l_dept_array nt_dept_detail;
Begin
OPEN dept_id;
FETCH dept_id BULK COLLECT INTO l_dept_array;
IF l_dept_array.COUNT() > 0 THEN
FORALL i IN 1..l_dept_array.COUNT SAVE EXCEPTIONS
EXECUTE IMMEDIATE 'INSERT INTO stg_emp SELECT
Dept,''DEPT_10'' FROM dept_emp'||dblink||' WHERE
dept_id = '||l_dept_array(i)||'';
COMMIT;
END IF;
CLOSE dept_id;
end abc;
Why are you bothering to use cursors, arrays etc in the first place? Why can't you just do a simple insert as select?
Problems with your procedure as listed above:
You don't declare procedures like Procedure abc () - for a standalone procedure, you would do create or replace procedure abc as, or in a package: procedure abc is
You reference a variable called "dblink" that isn't declared anywhere.
You didn't put end abc; at the end of your procedure (I hope that was just a mis-c&p?)
You're effectively doing a simple insert as select, but you're way over-complicating it, plus you're making your code less performant.
You've not listed the column names that you're trying to insert into; if stg_emp has more than two columns or ends up having columns added, your code is going to fail.
Assuming your dblink name isn't known until runtime, then here's something that would do what you're after:
create Procedure abc (dblink in varchar2)
is
begin
execute immediate 'insert into stg_emp select dept, ''DEPT_10'' from dept_emp#'||dblink||
' where dept_id in (select dept_ids from dept)';
commit;
end abc;
/
If, however, you do know the dblink name, then you'd just get rid of the execute immediate and do:
create Procedure abc (dblink in varchar2)
is
begin
insert into stg_emp -- best to list the column names you're inserting into here
select dept, 'DEPT_10'
from dept_emp#dblink
where dept_id in (select dept_ids from dept);
commit;
end abc;
/
There appears te be a lot wrong with this code.
1) why the execute immediate? Is there any explicit requirement for that? No, than don't use it
2) where is the dblink variable declared?
3) as Boneist already stated, why not a simple subselect in the insert statement?
INSERT INTO stg_emp SELECT
Dept,'DEPT_10' FROM dept_emp#dblink WHERE
dept_id in (select dept_ids from dept );
For one, it would make the code actually readable ;)

PL/SQL compile conditionally on existence of database object

Is it possible to have conditional compilation in Oracle, where the condition is the existence of a database object (specifically, a table or view or synonym)? I'd like to be able to do something like this:
sp_some_procedure is
$IF /*check if A exists.*/ then
/* read from and write to A as well as other A-related non-DML stuff...*/
$ELSE /*A doesn't exist yet, so avoid compiler errors*/
dbms_output.put_line('Reminder: ask DBA to create A!')
$ENDIF
end;
Yes it is. Here a sample where the first stored procedure wants to select from XALL_TABLES, but if this table doesn't exist, select from dual. Finally, because I haven't got an XALL_TABLES object, the first stored procedure selects from dual. The second one, does the same thing on the ALL_TABLES object. Because the ALL_TABLES exists, the second stored procedure selects from all_tables but not from DUAL.
This kind of construction is useful where the package have to be deployed on all your database and use tables that are not deployed everywhere ... (ok, perhaps there is a conceptual problem, but it happens).
--conditionals compilation instructions accept only static condition (just with constants)
--passing sql bind variable doesn't work
--To pass a value to a conditional compilation instruction, I bypasses the use of input parameters of the script
--these 4 next lines affect a value to the first and the second input parameter of the script
--If your originally script use input script parameter, use the next free parameter ...
column param_1 new_value 1 noprint
select nvl(max(1), 0) param_1 from all_views where owner = 'SYS' and view_name = 'XALL_TABLES';
column param_2 new_value 2 noprint
select nvl(max(1), 0) param_2 from all_views where owner = 'SYS' and view_name = 'ALL_TABLES';
CREATE or replace PACKAGE my_pkg AS
function test_xall_tables return varchar2;
function test_all_tables return varchar2;
END my_pkg;
/
CREATE or replace PACKAGE BODY my_pkg AS
function test_xall_tables return varchar2 is
vch varchar2(50);
begin
$IF (&1 = 0) $THEN
select 'VIEW XALL_TABLES D''ONT EXISTS' into vch from dual;
$ELSE
select max('VIEW XALL_TABLES EXISTS') into vch from XALL_TABLES;
$END
return vch;
end test_xall_tables;
function test_all_tables return varchar2 is
vch varchar2(50);
begin
$IF (&2 = 0) $THEN
select 'VIEW ALL_TABLES D''ONT EXISTS' into vch from dual;
$ELSE
select max('VIEW ALL_TABLES EXISTS') into vch from ALL_TABLES;
$END
return vch;
end test_all_tables;
END my_pkg;
/
the test :
select my_pkg.test_xall_tables from dual;
give
VIEW XALL_TABLES D'ONT EXISTS
select my_pkg.test_all_tables from dual;
give
VIEW ALL_TABLES EXISTS
I would use 'EXECUTE IMMEDIATE' and a EXCEPTION clause.
Use dynamic SQL to create package constants to track which objects exist, and then use those constants in conditional compilation.
--E.g., say there are two possible tables, but only one of them exists.
--create table table1(a number);
create table table2(a number);
--Create a package with boolean constants to track the objects.
--(Another way to do this is to use ALTER SESSION SET PLSQL_CCFLAGS)
declare
table1_exists_string varchar2(10) := 'true';
table2_exists_string varchar2(10) := 'true';
temp number;
begin
begin
execute immediate 'select max(1) from table1 where rownum <= 1' into temp;
exception when others then
table1_exists_string := 'false';
end;
begin
execute immediate 'select max(1) from table2 where rownum <= 1' into temp;
exception when others then
table2_exists_string := 'false';
end;
execute immediate '
create or replace package objects is
table1_exists constant boolean := '||table1_exists_string||';
table2_exists constant boolean := '||table2_exists_string||';
end;
';
end;
/
--Look at the results in the source:
select * from user_source where name = 'OBJECTS';
--Create the object that refers to the tables.
create or replace function compile_test return varchar2 is
v_test number;
begin
$if objects.table1_exists $then
select max(1) into v_test from table1;
return 'table1 exists';
$elsif objects.table2_exists $then
select max(1) into v_test from table2;
return 'table 2 exists';
$else
return 'neither table exists';
$end
end;
/
--Check the dependencies - only TABLE2 is dependent.
select * from user_dependencies where name = 'COMPILE_TEST';
--Returns 'table 2 exists'.
select compile_test from dual;
Mixing dynamic SQL, dynamic PL/SQL, and conditional compilation is usually a very evil idea. But it will allow you to put all of your ugly dynamic SQL in one installation package, and maintain real dependency tracking.
This may work well in a semi-dynamic environment; for example a program that is installed with different sets of objects but does not frequently change between them.
(Also, if the whole point of this is just to replace scary error messages with friendly warnings, in my opinion that is a very bad idea. If your system is going to fail, the failure should be obvious so it can be immediately fixed. Most people ignore anything that starts with "Reminder...".)
No - that is not possible... but if you create a stored procedure referencing a non-existent DB object and try to compile it the compilation will show errors... the stored procedure will be there but "invalid"... and the compilation errors are accessible for the DBA whenever he looks at it... so I would just go ahead and create all needed stored procedures, if any compilation errors arise ask the DBA (sometimes the object exists but the stored procedure need permissions to access it...)... after the reason for the error(s) is fixed you can just recompile the stored procedure (via ALTER PROCEDURE MySchema.MyProcName COMPILE;) and all is fine...
IF you don't want code to be there you can just DROP the strored procedure and/or replace is via CREATE OR REPLACE... with dbms_output.put_line('Reminder: ask DBA to create A!') in the body.
The only other alternative is as kevin points out EXECUTE IMMEDIATE with proper EXCEPTION handling...
What I would do is check the existence via all_objects, something like:
declare
l_check_sql varchar2(4000);
l_cnt number;
begin
l_check_sql := q'{
select count(1)
from all_objects
where object_name = 'MY_OBJ'
and owner = 'MY_OWNER'
}';
execute immediate l_check_sql into l_cnt;
if (l_cnt > 0) then
-- do something referring to MY_OBJ
else
-- don't refer to MY_OBJ
end if;
end;

How do I use CREATE OR REPLACE?

Am I correct in understanding that CREATE OR REPLACE basically means "if the object exists, drop it, then create it either way?"
If so, what am I doing wrong? This works:
CREATE TABLE foo (id NUMBER,
title VARCHAR2(4000) DEFAULT 'Default Title')
And this doesn't (ORA-00922: missing or invalid option):
CREATE OR REPLACE TABLE foo (id NUMBER,
title VARCHAR2(4000) DEFAULT 'Default Title')
Am I doing something stupid? I don't seem to be able to find much documentation about this syntax.
This works on functions, procedures, packages, types, synonyms, trigger and views.
Update:
After updating the post for the third time, I'll reformulate this:
This does not work on tables :)
And yes, there is documentation on this syntax, and there are no REPLACE option for CREATE TABLE.
One of the nice things about the syntax is that you can be sure that a CREATE OR REPLACE will never cause you to lose data (the most you will lose is code, which hopefully you'll have stored in source control somewhere).
The equivalent syntax for tables is ALTER, which means you have to explicitly enumerate the exact changes that are required.
EDIT:
By the way, if you need to do a DROP + CREATE in a script, and you don't care for the spurious "object does not exist" errors (when the DROP doesn't find the table), you can do this:
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE owner.mytable';
EXCEPTION
WHEN OTHERS THEN
IF sqlcode != -0942 THEN RAISE; END IF;
END;
/
There is no create or replace table in Oracle.
You must:
DROP TABLE foo;
CREATE TABLE foo (....);
CREATE OR REPLACE can only be used on functions, procedures, types, views, or packages - it will not work on tables.
Following script should do the trick on Oracle:
BEGIN
EXECUTE IMMEDIATE 'drop TABLE tablename';
EXCEPTION
WHEN OTHERS THEN
IF sqlcode != -0942 THEN RAISE;
END IF;
END;
-- To Create or Replace a Table we must first silently Drop a Table that may not exist
DECLARE
table_not_exist EXCEPTION;
PRAGMA EXCEPTION_INIT (table_not_exist , -00942);
BEGIN
EXECUTE IMMEDIATE('DROP TABLE <SCHEMA>.<TABLE NAME> CASCADE CONSTRAINTS');
EXCEPTION WHEN table_not_exist THEN NULL;
END;
/
Does not work with Tables, only functions etc.
Here is a site with some examples.
A usefull procedure for oracle databases without using exeptions (under circumstances you have to replace user_tables with dba_tables and/or constrain the tablespace in the query):
create or replace procedure NG_DROP_TABLE(tableName varchar2)
is
c int;
begin
select count(*) into c from user_tables where table_name = upper(tableName);
if c = 1 then
execute immediate 'drop table '||tableName;
end if;
end;
If you are doing in code then first check for table in database
by using query
SELECT table_name
FROM user_tables
WHERE table_name = 'XYZ'
if record found then truncate table otherwise create Table
Work like Create or Replace.
You can use CORT (www.softcraftltd.co.uk/cort). This tool allows to CREATE OR REPLACE table in Oracle.
It looks like:
create /*# or replace */ table MyTable(
... -- standard table definition
);
It preserves data.
So I've been using this and it has worked very well: - it works more like a DROP IF EXISTS but gets the job done
DECLARE
VE_TABLENOTEXISTS EXCEPTION;
PRAGMA EXCEPTION_INIT(VE_TABLENOTEXISTS, -942);
PROCEDURE DROPTABLE(PIS_TABLENAME IN VARCHAR2) IS
VS_DYNAMICDROPTABLESQL VARCHAR2(1024);
BEGIN
VS_DYNAMICDROPTABLESQL := 'DROP TABLE ' || PIS_TABLENAME;
EXECUTE IMMEDIATE VS_DYNAMICDROPTABLESQL;
EXCEPTION
WHEN VE_TABLENOTEXISTS THEN
DBMS_OUTPUT.PUT_LINE(PIS_TABLENAME || ' NOT EXIST, SKIPPING....');
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE(SQLERRM);
RAISE;
END DROPTABLE;
BEGIN
DROPTABLE('YOUR_TABLE_HERE');
END DROPTABLE;
/
Hope this helps
Also reference:
PLS-00103 Error in PL/SQL Developer
'Create or replace table' is not possible. As others stated, you can write a procedure and/or use begin execute immediately (...). Because I don't see an answer with how to (re)create the table, I putted a script as an answer.
PS: in line of what jeffrey-kemp mentioned: this beneath script will NOT save data that is already present in the table you are going to drop. Because of the risk of loosing data, at our company it is only allowed to alter existing tables on the production environment, and it is not allowed to drop tables. By using the drop table statement, sooner or later you will get the company police standing at your desk.
--Create the table 'A_TABLE_X', and drop the table in case it already is present
BEGIN
EXECUTE IMMEDIATE
'
CREATE TABLE A_TABLE_X
(
COLUMN1 NUMBER(15,0),
COLUMN2 VARCHAR2(255 CHAR),
COLUMN3 VARCHAR2(255 CHAR)
)';
EXCEPTION
WHEN OTHERS THEN
IF SQLCODE != -955 THEN -- ORA-00955: object name already used
EXECUTE IMMEDIATE 'DROP TABLE A_TABLE_X';
END IF;
END;
I would do something like this
begin
for i in (select table_name from user_tables where table_name = 'FOO') loop
execute immediate 'drop table '||i.table_name;
end loop;
end;
execute immediate 'CREATE TABLE FOO (id NUMBER,
title VARCHAR2(4000)) ';
If this is for MS SQL.. The following code will always run no matter what if the table exist already or not.
if object_id('mytablename') is not null //has the table been created already in the db
Begin
drop table mytablename
End
Create table mytablename (...

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