What is the correct way to rebuild an index of a specific constraint, without knowing the index name, since it might different between environments.
In this case, prefer not knowing the index name (existing condition), and not renaming it first.
ALTER INDEX (select index_name from user_constraints where constraint_name = upper('constraint123')) REBUILD;
I tried casting, string, as is... and getting the following error
ORA-00953: missing or invalid index name
ALTER INDEX (select index_name from user_constraints where constraint_name = 'constraint123') REBUILD
Any time you don't know an object name (table name, column name, etc..) you have to use dynamic SQL, and that requires PL/SQL. Here's how you would do it:
CREATE OR REPLACE PROCEDURE p_rebuild_constraint_index (in_constraint_name IN varchar2)
AS
var_index_name varchar2(128);
BEGIN
SELECT MAX(index_name)
INTO var_index_name
FROM user_constraints
WHERE constraint_name = in_constraint_name;
IF var_index_name IS NOT NULL
THEN
EXECUTE IMMEDIATE 'ALTER INDEX "'||var_index_name||'" REBUILD';
END IF;
END;
Then simply call it:
BEGIN p_rebuild_constraint_index('CONSTRAINT123'); END;
Related
I have a table called schema.exampletab, which has partitions where the partition name is on the form Pxxxxxx where the x's are partition periods (year and month YYYYMM) and then there is a local PK. I want to drop a partition, but I get the error message ORA-14006: Invalid partition name when attempting to drop it, but when I try to simply query data from a partition it selects and displays the data from the partition in question. Note that I am using a scheduler which uses date as a parameter using YYYYMMDD, so I usually substring.
For instance I can query data by using the following statement:
SELECT *
FROM schema.exampletab
PARTITION (P202110);
This returns 20 rows of data in my table.
I then try to drop the partition using the following statement:
ALTER TABLE schema.exampletab DROP PARTITION (concat(P,substr('20211011',1,6))
UPDATE INDEXES;
This however, leads to the ORA-14006 error message. In order to control that the partition exists I tried to look up that the schema, table, and partition exists in the all_tab_partitions where all partitions in the database I work on are logged.
select partition_name from all_tab_partitions
where table_owner = 'schema' and table_name = 'exampletab' and
substr(partition_name,2,7) = substr('20211022',1,6);
This returns the partition name P202110 in the query result.
I hoped I could use the drop partition with a subquery like this:
ALTER TABLE schema.exampletab DROP PARTITION select partition_name from all_tab_partitions
where table_owner = 'schema' and table_name = 'exampletab' and
substr(partition_name,2,7) = substr('20211022',1,6);
However, this still leads to ORA-14006 error. I have tried to write the partition name like 'P202110' and P202110 instead of the parenteces, but no luck.
How can I write the drop partition statement such that it drops the partition instead of giving the ORA-14006 error?
This is something which I have to do routinely and so it would be nice to know how to properly select and drop partitions, or truncate them, etc. Also, I use a scheduler which runs the sql queries at specified intervals so there I have to specify dates as a parameter, meaning that in my example code the YYYYMM is a parametervalue that gets parsed in and so I need to concactinate the P with this outputted parameter value, because if I type only P202110 it actually drops it.
You have two options, keeping in consideration that you are using sysdate to know which partition you should drop.
Option 1 -> Dynamic SQL and the result must be executed outside the query
select ' alter table '||table_owner||'.'||table_name||' drop partition '||partition_name||' update indexes ; '
from
dba_Tab_partitions
where table_owner = 'your_schema'
and table_name = 'your_table'
and partition_name = 'P'||substr(to_char(sysdate,'yyyymmdd'),1,6) ; ;
This query gives you the command output, but you need to execute it
alter table yourschema.yourtable drop partition P202110 update indexes;
Example in my own environment
SQL> select ' alter table '||table_owner||'.'||table_name||' drop partition '||partition_name||' update indexes ; '
from
dba_Tab_partitions
where table_owner = 'FDM_DATA'
and table_name = 'FDM_DIM_CUSTOMER'
and partition_name = 'P_'||substr(to_char(sysdate,'yyyymmdd'),1,6) ;
'ALTERTABLE'||TABLE_OWNER||'.'||TABLE_NAME||'DROPPARTITION'||PARTITION_NAME||'UP
--------------------------------------------------------------------------------
alter table FDM_DATA.FDM_DIM_CUSTOMER drop partition P_202110 update indexes ;
Option 2 -> PLSQL
A better option is to use PLSQL. A small example when you want to drop only one partition based on the current sysdate. You can extend / modify this code to cover any kind of time frame.
declare
v_owner varchar2(128) := 'YOUR_SCHEMA';
v_table_name varchar2(128) := 'YOUR_TABLE';
v_partition_name varchar2(128);
begin
select partition_name into v_partition_name from all_tab_partitions
where table_owner = v_owner and
table_name = v_table_name and
partition_name = 'P'||substr(to_char(sysdate,'yyyymmdd'),1,6) ;
execute immediate 'alter table '||v_owner||'.'||v_table_name||' drop partition '||v_partition_name||' update indexes' ;
exception
when no_data_found then null; -- if there is no partition, nothing to do and no error is raised
when others then raise;
end;
/
You cannot use "expressions" in partition name
This is wrong:
ALTER TABLE schema.exampletab DROP PARTITION (concat(P,substr('20211011',1,6))
UPDATE INDEXES;
this is correct:
ALTER TABLE schema.exampletab DROP PARTITION P20211011
UPDATE INDEXES;
You may use this code to drop partitions dynamically. Just update C_OWNER ,C_TABLE_NAME , C_PARTITION_TEMPLATE in the header. Please pay attention that the sql command is built dynamically, but when it is ready is has the partition name fully parsed.
declare
C_OWNER varchar2(128) := 'MYOWNER';
C_TABLE_NAME varchar2(128) := 'MYTABLE';
C_PARTITION_TEMPLATE varchar2(128) := '2011';
cursor part_cur is
select *
from all_tab_partitions
where table_owner=C_OWNER and
table_name = C_TABLE_NAME and
partition_name like '%'||C_PARTITION_TEMPLATE||'%'
order by partition_position;
BEGIN
for part_rec in part_cur loop
execute immediate 'ALTER TABLE "'||part_rec.table_owner||'"."'||part_rec.table_name||'"'||
' DROP PARTITION ("'||part_rec.partition_name||'") UPDATE INDEXES';
end loop;
END;
/
How do I delete all the tables I have in a specific schema? Only the tables in the schema should be deleted.
I already have all the table names that I fetched with the code below, but how do delete all those tables?
The following is some psycopg2 code, and below that is the SQL generated
writeCon.execute("SELECT table_name FROM information_schema.tables WHERE table_schema='mySchema'")
SELECT table_name FROM information_schema.tables WHERE table_schema='mySchema'
You can use an anonymous code block for that.
WARNING: This code is playing with DROP TABLE statements, and they are really mean if you make a mistake ;) The CASCADE option drops all depending objects as well. Use it with care!
DO $$
DECLARE
row record;
BEGIN
FOR row IN SELECT * FROM pg_tables WHERE schemaname = 'mySchema'
LOOP
EXECUTE 'DROP TABLE mySchema.' || quote_ident(row.tablename) || ' CASCADE';
END LOOP;
END;
$$;
In case you want to drop everything in your schema, including wrappers, sequences, etc., consider dropping the schema itself and creating it again:
DROP SCHEMA mySchema CASCADE;
CREATE SCHEMA mySchema;
For a single-line command, you can use psql and its \gexec functionality:
SELECT format('DROP TABLE %I.%I', table_schema, table_name)
FROM information_schema.tables
WHERE table_schema= 'mySchema';\gexec
That will run the query and execute each result string as SQL command.
I need to modify a table to remove the primary key constraint, the only problem is the table is generated by another system and I don't have the constraint name. So as a workaround I have created the following script which I thought should work but it's not, so can anyone please help me to write another script which will work.
ALTER TABLE temp
MODIFY CONSTRAINT (select constraint_name
FROM all_constraints
WHERE owner like '%tempUser%' and
table_name like '%temp%' and
constraint_type = 'P'
)
DISABLE;
I am getting following error when trying to run.
SQL Error: ORA-14006: invalid partition name
14006. 00000 - "invalid partition name"
*Cause: a partition name of the form is
expected but not present.
*Action: enter an appropriate partition name.
I tried following code based on suggested link and it run without any error but it does not remove the constraint.
BEGIN
FOR c IN
(SELECT c.owner, c.table_name, c.constraint_name
FROM all_constraints c
where owner like '%tempUser%' and table_name like '%temp%' and constraint_type = 'P')
LOOP
dbms_utility.exec_ddl_statement('alter table ' || c.table_name || ' modify CONSTRAINT ' || c.constraint_name || ' disable ');
END LOOP;
END;
/
You could use dynamic SQL to solve this. First find the name of your constraint and then create dynamic code to disable it.
Have a look at Disable all table constraints in Oracle, which is similar
I have some big tables (30+ columns) with NOT NULL constraints. I would like to change all those constraints to NULL. To do it for a single column I can use
ALTER TABLE <your table> MODIFY <column name> NULL;
Is there a way to do it for all columns in one request ? Or should I copy/paste this line for all columns (><) ?
Is there a way to do it for all columns in one request ?
Yes. By (ab)using EXECUTE IMMEDIATE in PL/SQL. Loop through all the columns by querying USER_TAB_COLUMNS view.
For example,
FOR i IN
( SELECT * FROM user_tab_columns WHERE table_name = '<TABLE_NAME>' AND NULLABLE='N'
)
LOOP
EXECUTE IMMEDIATE 'ALTER TABLE <TABLE_NAME> MODIFY i.COLUMN_NAME NULL';
END LOOP;
In my opinion, by the time you would write the PL/SQL block, you could do it much quickly by using a good text editor. In pure SQL you just need 30 queries for 30 columns.
For a single table you can issue a single alter table command to set the listed columns to allow null, which is a little more efficient than running one at a time, but you still have to list every column.
alter table ...
modify (
col1 null,
col1 null,
col3 null);
If you were applying not null constraints then this would be more worthwhile, as they require a scan of the table to ensure that no nulls are present, and (I think) an exclusive table lock.
You can query user_tab_cols and combine it with a FOR cursor & EXECUTE IMMEDIATE to modify all not null columns - the PL/SQL block for doing like that would look like so:
DECLARE
v_sql_statement VARCHAR2(2000);
BEGIN
FOR table_recs IN (SELECT table_name, column_name
FROM user_tab_cols
WHERE nullable = 'N') LOOP
v_sql_statement :=
'ALTER TABLE ' || table_recs.table_name || ' MODIFY ' || table_recs.column_name || ' NULL';
EXECUTE IMMEDIATE v_sql_statement;
END LOOP;
END;
If you want to do it for all columns in a database instead of the ones in current schema, you can replace user_tab_cols and put in dba_tab_cols; I'd just run the query in the FOR to ensure that the columns being fetched are indeed the correct ones to be modified
I need a script which creates table or if it already exist drops it, and when recreates table. After some research I have found out that CREATE OR REPLACE TABLE in pl/sql doesn't exist. So I come up with this script :
DECLARE
does_not_exist EXCEPTION;
PRAGMA EXCEPTION_INIT (does_not_exist, -942);
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE foobar';
EXCEPTION
WHEN does_not_exist
THEN
NULL;
END;
/
CREATE TABLE foobar (c1 INT);
Is there any proper way to achieve this functionality?
You really shouldn't be doing this in PL/SQL, tables created at runtime would be indicative of a flaw in your data model. If you're really convinced you absolutely have to do this then investigate temporary tables first. Personally, I'd reassess whether it's necessary at all.
You seem to be going for the EAFP as opposed to LBYL approach, which is described in a few answers to this question. I would argue that this is unnecessary. A table is a fairly static beast, you can use the system view USER_TABLES to determine whether it exists before dropping it.
declare
l_ct number;
begin
-- Determine if the table exists.
select count(*) into l_ct
from user_tables
where table_name = 'THE_TABLE';
-- Drop the table if it exists.
if l_ct = 1 then
execute immediate 'drop table the_table';
end if;
-- Create the new table it either didn-t exist or
-- has been dropped so any exceptions are exceptional.
execute immediate 'create table the_table ( ... )';
end;
/
Using a global temporary table would seem to be a better option. However, if you insist on dropping and re-adding tables at runtime you could query one of the _TABLES views (i.e. USER_TABLES, DBA_TABLES, ALL_TABLES) to determine if the table exists, drop it if it does, then create it:
SELECT COUNT(*)
INTO nCount
FROM USER_TABLES
WHERE TABLE_NAME = 'FOOBAR';
IF nCount <> 0 THEN
EXECUTE IMMEDIATE 'DROP TABLE FOOBAR';
END IF;
EXECUTE IMMEDIATE 'CREATE TABLE FOOBAR(...)';
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