Is there a query in db2 9.7 control center wherein I can't DELETE(DROP) all the contents of my schema (including the schema) at once?
My other option is to drop/delete the objects first and then DROP schema..
But I want to DROP THE ENTIRE SCHEMA WITH ALL OBJECTS at once.
DROP SCHEMA <schema_name> CASCADE/RESTRICT didn't work for me.
The ADMIN_DROP_SCHEMA procedure is what you're looking for.
The ADMIN_DROP_SCHEMA procedure is used to drop a specific schema and all objects contained in it.
http://publib.boulder.ibm.com/infocenter/db2luw/v9/topic/com.ibm.db2.udb.admin.doc/doc/r0022036.htm
First drop all the tables in the schema.
Then try to delete the schema using
DROP SCHEMA SCHEMA_NAME RESTRICT
webchain.in have sample java program, explains how to delete the schema using java program
in case drop schema fails after dropping all the tables with the error SQLCODE=-551, SQLSTATE=42501, try command
grant dbadm on database to USER_NAME
Related
We had one of the devs create a foreign data wrapper with these commands:
CREATE SERVER serverName FOREIGN DATA WRAPPER postgres_fdw OPTIONS (xxxx);
CREATE USER MAPPING FOR user SERVER foreign_db OPTIONS (user 'xxxx', password 'xxxx');
CREATE SCHEMA foreign_db;
IMPORT FOREIGN SCHEMA public FROM SERVER serverName INTO foreign_db;
To drop this schema the suggestion was to run:
DROP SCHEMA if exists foreign_db cascade;
DROP USER mapping if exists for user server foreign_db;
DROP SERVER if exists serverName;
In the spec I see this for CASCADE:
Automatically drop objects (tables, functions, etc.) that are
contained in the schema, and in turn all objects that depend on those
objects
what concerns me is this line:
and in turn all objects that depend on those objects
My question is there a possibility of dropping anything outside of foreign_db schema and if yes, how can I check it?
Thank you.
It is possible that the command drops something outside the schema. Consider this:
create schema example;
create table example.my_table (id int);
create view public.my_view as select * from example.my_table;
If the schema is dropped with the cascade option, public.my_view will also be dropped. However, the behavior is logical and desirable.
You can check this executing these commands one by one:
begin;
drop schema example cascade;
rollback;
The schema will not be dropped and after drop... you should get something like this:
NOTICE: drop cascades to 2 other objects
DETAIL: drop cascades to table example.my_tabledrop cascades to view my_view
Alternatively, you can use the system catalog pg_depend, see this answer How to list tables affected by cascading delete.
How to create and use Synonyms on PostgreSQL as in Oracle. Do I need to create some DB link or any thing else. I could not find any good official doc on this topic.
Edit 1
Actually as of now i have an application which has two separate modules which connects with two different oracle databases; One modules need to access tables of other so for which we use synonyms over db link in oracle. Now we are migrating application to postgresql, so we need synonyms.
Edit 2
When i say two different oracle databases it means it can be two different oracle instances or two schemas of same db, it is configurable in application and application must support both modes.
PostgreSQL version: 9.6.3
Approach 1:-
Finally i got it working using foreign data wrapper postgres_fdw as below
I have two databases named dba and dbb. dbb has a table users and i need to access it in dba
CREATE SERVER myserver FOREIGN DATA WRAPPER postgres_fdw OPTIONS (host 'localhost', dbname 'dbb', port '5432');
CREATE USER MAPPING FOR postgres
SERVER myserver
OPTIONS (user 'user', password 'password');
CREATE FOREIGN TABLE users (
username char(1))
SERVER myserver
OPTIONS (schema_name 'public', table_name 'users');
CREATE FOREIGN TABLE users (users char(1));
Now i can execute all select/update queries in dba.
Approach 2:-
Can be achieved by creating two schemas in same db, below are the steps:
create two schemas ex app_schema, common_schema.
Grant access:
GRANT CREATE,USAGE ON SCHEMA app_schema TO myuser;
GRANT CREATE,USAGE ON SCHEMA common_schema TO myuser;
Now set search path of user as below
alter user myuser set search_path to app_schema,common_schema;
Now tables in common_schema will be visible to myuser. For example let say we have a table user in common_schema and table app in app_schema then below queries will be running easily:
select * from user;
select * from app;
This is similar to synonyms in oracle.
Note- Above queries will work PostgreSQL 9.5.3+
I think you don't need synonyms in Postgres the way you need them in Oracle because unlike Oracle there is a clear distinction between a user and a schema in Postgres. It's not a 1:1 relationship and multiple users can easily use multiple schemas without the need to fully qualify the objects by exploiting Postgres' "search path" feature - mydb.public.mytable.
If the tables are supposed to be in a different database in PostgreSQL as well, you'd create a foreign table using a foreign data wrapper.
If you used the Oracle synonym just to avoid having to write atable#dblink, you don't have to do anything in PostgreSQL, because foreign tables look and feel just like local tables in PostgreSQL.
If you use the synonym for some other purposes, you can either set search_path to include the schema where the target table is, or you can create a simple view that just selects everything from the target table.
I had a schema in one oracle DB as ui_prod. I asked my DBA team guys to create exactly same schema like ui_prod but as read only and name it ui_prod_readonly. Usually I will use Oracle SQL developer to connect a DB and query directly with table name like below.
--Connect to ui_prod
select * from table
but why I requested to put owner name infront when query for readonly schema they created for me, as without putting it, I get error table not exist.
--Connect to ui_prod_readonly
select * from ui_prod.table
I have project files which hardcode the sql query with only table names and adding owner name in front will cause many changes and effort. Can anyone explain me on this? or provide me any document/link to read. Thanks
You should look into synonyms, apparently the user you are connecting to the database as is not the owner of the objects. So to view the object you have to prepend the names with the schema name (the owner of the object themselves).
http://www.techonthenet.com/oracle/synonyms.php
CREATE OR REPLACE SYNONYM ui_prod_readonly.synonym_name
FOR ui_prod.object_name
It seems to me that your dbas have not created another set of tables but just granted the existing tables to the user ui_prod_readonly.
When you log in to Oracle, the current schema is the name of the user you used to log in. So if you log in with ui_prod_readonly Oracle checks that schema for the table if you do not qualify it with the owner (=schema).
If you want to change the current schema so that you don't need to fully qualify the tables, you can do that with ALTER SESSION
alter session set current_schema = ui_prod;
Once you have done that, you don't need to fully qualify the table with the owner (=schema).
if you need a user to read the data only
its simple to create new user and grant it only select privilege
you can create user and grant select privilege using
CREATE USER [user] IDENTIFIED BY [your_password];
grant select on table to [user]
I am trying to drop a user-defined database, like so:
create database demo;
drop database demo;
But I get the error
Cannot drop the database 'demo',
because it does not exist or you do
not have permission.
One way to sort this out might be to run
SELECT name FROM sys.databases
to see if the database does exist.
Some helpful tips from MSDN:
To use DROP DATABASE, the database
context of the connection cannot be
the same as the database to be
dropped. You could change your
context to, for example USE master
before running DROP
To execute DROP DATABASE, at a
minimum, a user must have CONTROL
permission on the database.
You might find some other useful information there that applies to your specific situation.
create database demo;
drop database demo;
In the above code, if the database is deleted and again tried to delete the database which does not exists will give you the error as you mentioned
How would I drop a schema and all of its contents, using SQL, in DB2 8.x without knowing what the content is?
I do not have a schema to drop at hand, but the infocenter (http://publib.boulder.ibm.com/infocenter/db2luw/v8/index.jsp?topic=/com.ibm.db2.udb.doc/admin/t0005230.htm) says that a DROP SCHEMA [schema name] shall work on DB2 8.x
EDIT: Ok, the Infocenter also says: "Before dropping a schema, all objects that were in that schema must be dropped themselves or moved to another schema"
So, need to drop all the objects in the schema first. The objects (tables, views, triggers, procedures, indexes...) can be listed quering the catalog views in SYSIBM schema.
E.g. to get all tables that belong to schema, run:
select table_name from sysibm.tables where table_schema = '[your schema name]'
Check the other sysibm views to get all objects that belong into a schema. the views are: sysibm.views, sysibm.triggers, sysibm.routines, sysibm.indexes, ... - consult IBM's Infocenter (the link above) for details.
use the comand centre-GUI to drop all contents of the schema, then DROP SCHEMA