I have about 30 tables in Oracle. Names of the tables have some template format, for example:
DF_D_AUTO, DF_D_PERSON
and so on. So the first part of a table name is always
DF_D_
I would like to clear all these tables. Of course I can clear them manually one by one.
However I would like to know may be someone knows a good fast way using SQL to clear all such tables in one scope.
You can run a loop on all such tables
BEGIN
for table_names in (select table_name from dba_tables where table_name like 'DF\_D\_%' escape '\')
loop
EXECUTE immediate 'truncate table ' || table_names.table_name;
end loop;
END;
DBA_TABLES - reference
Difference between dba_tables, user_tables, all_tables - reference
Related
I would be interested to drop all tables in a Redshift schema. Even though this solution works
DROP SCHEMA public CASCADE;
CREATE SCHEMA public;
is NOT good for me since that it drops SCHEMA permissions as well.
A solution like
DO $$ DECLARE
r RECORD;
BEGIN
-- if the schema you operate on is not "current", you will want to
-- replace current_schema() in query with 'schematodeletetablesfrom'
-- *and* update the generate 'DROP...' accordingly.
FOR r IN (SELECT tablename FROM pg_tables WHERE schemaname = current_schema()) LOOP
EXECUTE 'DROP TABLE IF EXISTS ' || quote_ident(r.tablename) || ' CASCADE';
END LOOP;
END $$;
as reported in this thread How can I drop all the tables in a PostgreSQL database?
would be ideal. Unfortunately it doesn't work on Redshift (apparently there is no support for for loops).
Is there any other solution to achieve it?
Run this SQL and copy+paste the result on your SQL client.
If you want to do it programmatically you need to built little bit code around it.
SELECT 'DROP TABLE IF EXISTS ' || tablename || ' CASCADE;'
FROM pg_tables
WHERE schemaname = '<your_schema>'
I solved it through a procedure that deletes all records. Using this technique to truncate fails but deleting it works fine for my intents and purposes.
create or replace procedure sp_truncate_dwh() as $$
DECLARE
tables RECORD;
BEGIN
FOR tables in SELECT tablename
FROM pg_tables
WHERE schemaname = 'dwh'
order by tablename
LOOP
EXECUTE 'delete from dwh.' || quote_ident(tables.tablename) ;
END LOOP;
RETURN;
END;
$$ LANGUAGE plpgsql;
--call sp_truncate_dwh()
In addition to demircioglu's answer, I had to add Commit after every drop statement to drop all tables in my schema. SELECT 'DROP TABLE IF EXISTS ' || tablename || ' CASCADE; COMMIT;' FROM pg_tables WHERE schemaname = '<your_schema>'
P.S.: I do not have required reputation to add this note as a comment and had to add as an answer.
Using Python and pyscopg2 locally on my PC I came up with this script to delete all tables in schema:
import psycopg2
schema = "schema_to_be_deleted"
try:
conn = psycopg2.connect("dbname='{}' port='{}' host='{}' user='{}' password='{}'".format("DB_NAME", "DB_PORT", "DB_HOST", "DB_USER", "DB_PWD"))
cursor = conn.cursor()
cursor.execute("SELECT tablename FROM pg_tables WHERE schemaname = '%s'" % schema)
rows = cursor.fetchall()
for row in rows:
cursor.execute("DROP TABLE {}.{}".format(schema, row[0]))
cursor.close()
conn.commit()
except psycopg2.DatabaseError as error:
logger.error(error)
finally:
if conn is not None:
conn.close()
Replace correctly values for DB_NAME, DB_PORT, DB_HOST, DB_USER and DB_PWD to connect to the Redshift DB
The following recipe differs from other answers in the regard that it generates one SQL statement for all tables we're going to delete.
SELECT
'DROP TABLE ' ||
LISTAGG("table", ', ') ||
';'
FROM
svv_table_info
WHERE
"table" LIKE 'staging_%';
Example result:
DROP TABLE staging_077815128468462e9de8ca6fec22f284, staging_abc, staging_123;
As in other answers, you will need to copy the generated SQL and execute it separately.
References
|| operator concatenates strings
LISTAGG function concatenates every table name into a string with a separator
The table svv_table_info is used because LISTAGG doesn't want to work with pg_tables for me. Complaint:
One or more of the used functions must be applied on at least one user created tables. Examples of user table only functions are LISTAGG, MEDIAN, PERCENTILE_CONT, etc
UPD. I just now noticed that SVV_TABLE_INFO page says:
The SVV_TABLE_INFO view doesn't return any information for empty tables.
...which means empty tables will not be in the list returned by this query. I usually delete transient tables to save disk space, so this does not bother me much; but in general this factor should be considered.
I am trying to derive a table with counts from multiple tables. The tables are not on my schema. The table names on the schema that I am interested in all start with 'STAF_' and end with '_TS'. The criteria i am looking for is where SEP = 'MO'. So for example, the query in its base form is:
select area, count(SEP) areacount
from mous.STAF_0001_TS
where SEP = 'MO'
group by area;
I have about 1000 tables that i'd like to do this for.
Ultimatly, I'd like the output to be a table on my schema that looks like the following:
area| areacount
0001| 3
0002| 7
0003| 438
Thank you.
As a first step I'd write an SQL query that generates an SQL query:
SELECT 'SELECT area, count(*) FROM '||c.table_name||'UNION ALL' as run_me
FROM all_tables c
WHERE c.table_name LIKE 'STAF\_%\_MS' escape '\'
Running this will produce an output that is another SQL query. Copy the result text out of your results grid and paste it back into your query pane. Delete the final UNION ALL and run it
Once you dig how to write an SQL query that generate an SQL query, you can look at turning it into a view, or creating a dynamic query in a string.
Gotta say, this is a horrible way to store data; you'd be better off using ONE table with an extra column containing whatever is in xxx of STAF_xxx_MS right now
In Oracle 12c, you can embed a FUNCTION that will query the number of rows in any given table. Then you can use that function in your main query. Here is an example:
WITH FUNCTION cnt ( p_owner VARCHAR2, p_table_name VARCHAR2 ) RETURN NUMBER IS
l_cnt NUMBER;
BEGIN
EXECUTE IMMEDIATE 'SELECT count(*) INTO :cnt FROM ' || p_owner || '.' || p_table_name INTO l_cnt;
RETURN l_cnt;
EXCEPTION WHEN OTHERS THEN
RETURN NULL; -- This will happen for entries in ALL_TABLES that are not directly accessible (e.g., IOT overflow tables)
END cnt;
SELECT t.owner, t.table_name, cnt(t.owner, t.table_name)
FROM all_tables t
where t.table_Name like 'STAF\_%\_MS' escape '\';
I need help in optimizing this query to use bulk collect and forall statements. I have created backup tables (BCK_xxxx) to copy all data from original tables (ORIG_xxx) but I am having problems converting this to bulk collect. Most examples I saw in BULK collect includes already defining the table name and structure using %rowtype. However, I have hundreds of tables to backup so I need my query specifically the table name to be dynamic. This my original query that inserts/deleted data one by one without bulk collect and takes a lot of time:
DECLARE
--select all table names from backup tables (ex: BCK_tablename)
CURSOR cur_temp_tbl IS
SELECT table_name
FROM all_tables
WHERE OWNER = 'BCKUP'
ORDER BY 1;
--select all table names from original tables (ex: ORIG_tablename)
CURSOR cur_original_tbl IS
SELECT table_name
FROM all_tables
WHERE OWNER = 'ORIG'
ORDER BY 1;
l_tbl_nm VARCHAR2(30 CHAR);
BEGIN
--first loop to delete all tables from backup
FOR a IN cur_temp_tbl LOOP
l_tbl_nm := a.table_name;
EXECUTE IMMEDIATE 'DELETE FROM '|| l_tbl_nm;
l_deleted_cnt := l_deleted_cnt +1;
END LOOP;
--second loop to insert data from original to backup
FOR b IN cur_original_tbl LOOP
l_tbl_nm := b.table_name;
CASE
WHEN INSTR(l_tbl_nm,'ORIG_') > 0 THEN
l_tbl_nm := REPLACE(l_tbl_nm,'ORIG_','BCK_');
ELSE
l_tbl_nm := 'BCK_' || l_tbl_nm;
END CASE;
EXECUTE IMMEDIATE 'INSERT INTO ' || l_tbl_nm || ' SELECT * FROM ' || b.table_name;
l_inserted_cnt := l_inserted_cnt +1;
END LOOP;
dbms_output.put_line('Deleted/truncated tables from backup :' ||l_deleted_cnt);
dbms_output.put_line('No of tables inserted with data from original to backup :' ||l_inserted_cnt);
EXCEPTION
WHEN OTHERS THEN
dbms_output.put_line(SQLERRM);
dbms_output.put_line(l_tbl_nm);
END;
I am thinking of including the code below to add after my second loop but I am having problems how to declare the 'cur_tbl' cursor and 'l_tbl_data' TABLE data type. I am unable to use rowtype since the tablename should be dynamic and will change in each iteration of my second loop that will list all table names from original table:
TYPE CurTblTyp IS REF CURSOR;
cur_tbl CurTblTyp;
TYPE l_tbl_t IS TABLE OF tablename.%ROWTYPE;
l_tbl_data l_tbl_t ;
OPEN cur_tbl FOR 'SELECT * FROM :s ' USING b.table_name;
FETCH cur_tbl BULK COLLECT INTO l_tbl_data LIMIT 5000;
EXIT WHEN cur_tbl%NOTFOUND;
CLOSE cur_tbl;
FORALL i IN 1 .. l_tbl_data .count
EXECUTE IMMEDIATE 'insert into '||l_tbl_nm||' values (:1)' USING
l_tbl_data(i);
Hope you can help me and suggest how I can make this code much simpler. Thanks a lot.
It looks like you want to remove all rows from the existing backup tables, then re-copy the entire contents from the original tables to the backup tables. If this is correct, using DELETE for the deletion and any loop operation for the insert will be slow.
First, to remove the data, use TRUNCATE. Since you are going to repopulate, use the REUSE STORAGE option. This is the most efficient way to delete all rows from the table.
TRUNCATE TABLE <backup table> REUSE STORAGE;
Second, to repopulate, just INSERT with a SELECT.
INSERT INTO <backup table> SELECT * FROM <orig table>;
You can use these in your loops as you loop by table. No need to cursor through the table rows as this will be faster.
If you have a new table, you can do something similar with a CTAS...
CREATE TABLE <backup table> AS SELECT * FROM <orig_table>;
There is a 3rd option in addition to the delete and truncate options: that's rename/drop. You rename the old back up tables, recreate the new backups (CTAS). If the create - insert is successful you drop the renamed tables, if the new backup fails you rename the prior old backups back to the initial backup names. You basically trade temporary usage of disk space for redo logs.
You don't need bulk processing, CTAS is still faster than bulk processing.
Have you used FORCE DELETE?
It was first introduced by the Oracle Master J.B.E
it is used to delete the data and ignores the constraint that the table may have and is a lot more faster than other delete statements.
FORCE DELETE FROM <table_name>;
In my PostgreSQL 9.2 database there are many tables having name with mixed cases,For example
Tbl_Sales,Tbl_Purch,Tbl_logMnth
What I want to do is
alter table "Table1" rename to table1
but how to rename all mixed-case tables in my database in an easy way ?
this is the query to use
ALTER TABLE name
RENAME TO new_name
Use the following select to get the table(s) with mixed-cases in name
SELECT table_name ucase,lower(table_name) lcase
FROM information_schema.tables
where table_type = 'BASE TABLE' and
table_schema = 'public' and
table_name ~ E'^[[:upper:]][^[:upper:]]'
PostgreSQL string function lower and information_schema.tables
and use PL/PGSQL SQL - DO to rename all tables that have mixed-case
do
$$
declare
rw record;
begin
for rw in
SELECT 'ALTER TABLE "'||t.ucase||'" RENAME to '||t.lcase||';' execme from (
SELECT table_name ucase, lower(table_name) lcase
FROM information_schema.tables
where table_type = 'BASE TABLE' and
table_schema = 'public' and
table_name ~ E'^[[:upper:]][^[:upper:]]')t
loop
execute rw.execme ;
end loop;
end;
$$
Your best bet would probably be to generate a series of dynamic SQL statements, in, say, Python or similar by querying the pg_tables catalog.
You could then iterate over that list for the schemas in which you're interested (or all of them if you want to do that, so long as they're user-created -- you should avoid any of the pg_ ones, among others, as those are managed by Postgres itself) and check to see if the lowercase name is the same as the current name. If they are different, you can then generate the ALTER TABLE statement needed to rename the table, and then execute it, making sure to COMMIT your changes.
sqlfiddle with an example of this.
Note how the foo table I created is listed in there.
I'd recommend white-listing by schema, say, public and any others you want. In the fiddle, for example, you wouldn't want to touch anything in the pg_catalog nor information_schema schemas. You could also filter by tableowner -- you would probably want to avoid, for example, anything owned by the postgres user.
Also, note that when creating tables, casing doesn't matter. If a table foo already exists, and I then try to create Foo, the error ERROR: relation "foo" already exists will result.
I am in the process of migrating a SQL Server database to Oracle, where I have to convert SQL Server procedure which uses special tables called INSERTED and DELETED in SQL Server.
As per my understanding these tables hold copies the data of last inserted/deleted records.
(find the msdn article here: http://msdn.microsoft.com/en-us/library/ms191300.aspx)
Are there any similar tables in Oracle to achieve this..? Please advise.
UPDATE:
Thanks for your answers and comments ,I think I need to explain the situation some more. Here is the full story to understand the real scenario;
Data base contains tables and shadow tables (shadow has an additional column).
When a table is updated same changes should be recorded in relevant shadow table with some additional data.
For this purpose they are having triggers for each table (these triggers copy data to relevant shadow table).
The above mentioned procedure generates these triggers dynamically for each and every table.
Now the real problem is I don't have the knowledge about the columns as triggers are dynamically generated for each table.
Basically I can’t get value like: NEW.col_1 or: OLD.col_1 as APC mentioned. Can I.?
Or else I have to write all those triggers manually using prefixes: NEW and: OLD rather than trying to generate them dynamically.
I am using Oracle 11g
Oracle triggers use pseudo-records rather than special tables. That is, instead of tables we can access the values of individual columns.
We distinguish pseudo-records in the affected table from records in (other) tables by using the prefixes :NEW and :OLD . Oracle allows us to declare our own names for these, but there is really no good reason for abandoning the standard.
Which column values can we access?
Action :OLD :NEW
------ ---- ----
INSERTING n/a Inserted value
UPDATING Superseded value Amended value
DELETING Deleted value n/a
You will see that :OLD is the same as the MSSQL table DELETED and :NEW is the same as table INSERTED
So, to trigger a business rule check when a certain column is updated:
create or replace trigger t23_bus_check_trg
before update on t23
for each row
begin
if :NEW.col_1 != :OLD.col_1 then
check_this(:NEW.col_1 , :OLD.col_1);
end if;
end t23_bus_check_trg;
There's a whole chapter on records in the PL/SQL Reference. Find out more.
There are many differences between Sql Server triggers and Oracle triggers. In Oracle, you can declare statement level or row level triggers. Sql Server only has statement level. In Oracle, you can declare before triggers or after triggers. Sql Server only has after triggers.
If you're going to be working with Oracle, although later versions have the compound trigger, get used to working with row level triggers. There you have the pseudo row designation of :old and :new, kinda like Deleted and Inserted except it's just the one row of data. It's like being in a cursor loop, something you can do in Sql Server, but cursor perform so poorly in Sql Server, developers go to great lengths to avoid them. They are commonly used in Oracle.
The general rule of thumb is this: if you need to examine the data and possibly alter it before it goes to the table, use a "before" trigger. If you want to perform an audit or logging procedure, use an "after" trigger.
The page I linked to above gives a lot of technical details, but it is absolutely atrocious at giving usable examples. For that, just google "oracle trigger tutorial" and you should get lots of handy, easy-to-learn-from examples.
Thanks for the answers and comments. here is the complete solution to my problem.If some one meet the exact problem this will help.
create or replace PROCEDURE CreateTrackingTriggers
(
-- take the target table and shadow user as agruments
v_TableName IN NVARCHAR2 DEFAULT NULL,
v_ShadowUser IN NVARCHAR2 DEFAULT 'SHADOW_USER'
)
AUTHID CURRENT_USER -- grant permission to create triggers
AS
v_TriggerName NVARCHAR2(500);
v_ColList NVARCHAR2(2000);
v_ColList_shadow NVARCHAR2(2000);
v_SQLCommand VARCHAR2(4000);
v_ColName NVARCHAR2(500);
v_ColSize NUMBER(10,0);
v_Prefix NVARCHAR2(500);
v_count NUMBER(1,0);
BEGIN
DECLARE
-- define a cursor to get the columns of the target table. order by COLUMN_ID is important
CURSOR Cols
IS SELECT COLUMN_NAME , CHAR_COL_DECL_LENGTH FROM USER_TAB_COLS
WHERE TABLE_NAME = upper(v_TableName) order by COLUMN_ID;
-- define a cursor to get the columns of the target shadow table order by COLUMN_ID is important
CURSOR Shadow_Cols
IS SELECT COLUMN_NAME , CHAR_COL_DECL_LENGTH FROM ALL_TAB_COLS
WHERE TABLE_NAME = upper(v_TableName) and upper(owner)=upper(v_ShadowUser) order by COLUMN_ID;
BEGIN
-- generate the trigger name for target table
v_TriggerName := 'TRG_' || upper(v_TableName) || '_Track' ;
-- check v_count , determine whether shdow table exist if not handle it
select count(*) into v_count from all_tables where table_name = upper(v_TableName) and owner = upper(v_ShadowUser);
-- iterate the cursor. generating column names prefixing ':new.'
OPEN Cols;
FETCH Cols INTO v_ColName,v_ColSize;
WHILE Cols%FOUND
LOOP
BEGIN
IF v_ColList IS NULL THEN
v_ColList := ':new.'||v_ColName ;
ELSE
v_ColList := v_ColList || ',' || ':new.'||v_ColName;
END IF;
FETCH Cols INTO v_ColName,v_ColSize;
END;
END LOOP;
CLOSE Cols;
-- iterate the cursor. get the shadow table columns
OPEN Shadow_Cols;
FETCH Shadow_Cols INTO v_ColName,v_ColSize;
WHILE Shadow_Cols%FOUND
LOOP
BEGIN
IF v_ColList_shadow IS NULL THEN
v_ColList_shadow := v_ColName;
ELSE
v_ColList_shadow := v_ColList_shadow || ',' || v_ColName;
END IF;
FETCH Shadow_Cols INTO v_ColName,v_ColSize;
END;
END LOOP;
CLOSE Shadow_Cols;
-- create trigger command. This will generate the trigger that dupilicates target table's data into shdow table
v_SQLCommand := 'CREATE or REPLACE TRIGGER '||v_TriggerName||'
AFTER INSERT OR UPDATE OR DELETE ON '||upper(v_TableName)||'
REFERENCING OLD AS old NEW AS new
FOR EACH ROW
DECLARE
ErrorCode NUMBER(19,0);
BEGIN
-- v_ColList_shadow : shdow table column list
-- v_ColList : target table column list with :new prefixed
INSERT INTO '|| v_ShadowUser ||'.'||upper(v_TableName)||'('||v_ColList_shadow||') values ('||v_ColList||');
EXCEPTION
WHEN OTHERS THEN ErrorCode := SQLCODE;
END;';
EXECUTE IMMEDIATE v_SQLCommand;
END;
END;