Am I correct to think that listing indexes for materialized views is the same as listing indexes for tables? In other words:
select *
from ALL_IND_COLUMNS
where TABLE_OWNER='SOME_OWNER'
and TABLE_NAME='SOME_TABLE'
order by INDEX_NAME, COLUMN_POSITION;
It is, yes.
When you create a materialized view, you are actually creating a table of the same name as well. If you look at ALL_OBJECTS, you'll see both a table and a materialized view with the same name
SELECT owner, object_name, object_type
FROM all_objects
WHERE owner = 'SOME_OWNER'
AND object_name = 'SOME_TABLE'
Related
I have some SQL scripts; one of them references an object called "names". I can:
select * from names
and it returns results. However, I cannot see a table called "names". Neither can I see a view called "names". I can't find a custom type called "names".
If I look for one of the columns that is returned by the query select * from names using:
select * from sys.all_tab_columns where column_name like '%MyColumn%'
it finds a table called LSNAMES, but that has no rows.
Any ideas how I can find this "table"?
I'd start the research with understanding what type of object this is:
SELECT owner, object_name, object_type
FROM all_objects
WHERE object_name = 'NAMES'
Once you have a type, you could query some more information from all_<type>s
Look for:
A materialized view called NAMES
SELECT * FROM ALL_MVIEWS WHERE MVIEW_NAME = 'NAMES';
A synonym called NAMES
SELECT * FROM ALL_SYNONYMS WHERE SYNONYM_NAME = 'NAMES';
I need to create materialized view test without data then I will create a script to insert data into this materialized view for the first time. After this I will run materialized view refresh to refresh the view every night.
As I am not expert in materialized views can anyone help me here.
At present I have script to create materialized view which is running for 2 hours for 20 million rows.
create materialize view
If I understand the question correctly, you want to break up the MV creation into separate steps:
Create an empty table / materialized view.
Populate it.
Schedule a nightly refresh process.
For this you can use the on prebuilt table clause to change a normal table into a materialized view.
Demo source table:
create table demo_source (id, name) as
select 1, 'Red' from dual union all
select 2, 'Yellow' from dual union all
select 3, 'Orange' from dual union all
select 4, 'Blue' from dual;
New table which is going to be our MV (you could also populate it with the create table as select, or you could create it using explicit column names, datatypes, constraints, partitioning etc like any normal table):
create table demo_mv as
select * from demo_source s
where 1 = 2;
Populate it using a separate insert step:
insert into demo_mv
select * from demo_source;
Now we convert it from a regular table into an MV:
create materialized view demo_mv on prebuilt table
as
select * from demo_source;
Now DEMO_MV is a materialized view.
If I were you, I'd create the materialized view "as is" (i.e. no restrictions you mentioned).
Anyway: the simplest option is to include the false condition in the WHERE clause which creates the object without data, such as
SQL> create materialized view mv_dept as
2 select * from dept
3 where 1 = 2; --> this
Materialized view created.
SQL> select * from mv_dept;
no rows selected
SQL> desc mv_dept;
Name Null? Type
----------------------------- -------- --------------------
DEPTNO NOT NULL NUMBER(2)
DNAME VARCHAR2(14)
LOC VARCHAR2(13)
SQL>
I know this question was asked specifically about Oracle, but I got here looking for the same question about Postgres.
Luckily, Postgres has a 'WITH NO DATA' clause at the end of the materialized view statement that just creates the view but does not populate data into it. It can still be refreshed on-demand the same way after that.
https://www.postgresql.org/docs/current/sql-creatematerializedview.html
I have the same problem. At deploy time I don't want that the refresh takes to0 much time. So here I think is a better solution.
drop materialized view test_mv;
create materialized view test_mv
as select * from all_objects
where 1 = ( select count(*) from user_tables where table_name = 'TEST_MV' ) ;
select * From test_mv
=> null
exec DBMS_MVIEW.REFRESH('TEST_MV', method => 'C', atomic_refresh => FALSE, out_of_place => false , PARALLELISM => 4);
select * From test_mv
=> result is now of all objects
I'm new in Oracle. I have a table that lists tablenames of database. Its name is "AD_Table". I want to select ID table, and createdby from ad_table list. For example in ad_table it has one column name tablename that represents table name in database:
tablename
---------
AD_Tab1
AD_Tab2
AD_Tab3
AD_Tab4
AD_Tab5
AD_Tab6
AD_Tab7
AD_Tab8
AD_Tab9
AD_Tab10
I want query like this :
SELECT
createdby
from (SELECT TABLENAME FROM AD_TABLE)
but it won't work. Can anyone help?
In Oracle you can have many tables with the same name, on different schemas;
assuming that you need to find all the tables, and their owners, whose names are contained in your table, you can try with something like this:
select owner, table_name
from AD_table AD
inner join dba_tables DBA ON ( dba.table_name = UPPER(ad.tableName))
Notice that you need to log in with a user having rights to make a select on DBA_TABLES to run this query.
For a table in oracle, I can query "all_tab_columns" and get table column information, like the data type, precision, whether or not the column is nullable.
In SQL Developer or TOAD, you can click on a view in the GUI and it will spit out a list of the columns that the view returns and the same set of data (data type, precision, nullable, etc).
So my question is, is there a way to query this column definition for a view, the way you can for a table? How do the GUI tools do it?
You can use user_tab_columns (or all_tab_columns and dba_tab_columns respectively) regardless if table_name refers to a view or a table.
View columns appear in all_tab_columns, so you can query them just as you can tables.
Just simply write this query:
SQL> desc TABLE/VIEW NAME;
For example if the table/view name is "department" Then just write:
SQL> desc department;
This will give the list of all fields, it's type and default Null info of the table or view.
you can use the ANSI catalog views, should work for most RDBMs
select *
from information_schema.columns c
join information_schema.tables t on c.table_name = t.table_name
where table_type = 'view'
I want to find the foreign keys of a table but there may be more than one user / schema with a table with the same name. How can I find the one that the currently logged user is seeing? Is there a function that gives its owner? What if there are public synonyms?
You can query the ALL_OBJECTS view:
select owner
, object_name
, object_type
from ALL_OBJECTS
where object_name = 'FOO'
To find synonyms:
select *
from ALL_SYNONYMS
where synonym_name = 'FOO'
Just to clarify, if a user user's SQL statement references an object name with no schema qualification (e.g. 'FOO'), Oracle FIRST checks the user's schema for an object of that name (including synonyms in that user's schema). If Oracle can't resolve the reference from the user's schema, Oracle then checks for a public synonym.
If you are looking specifically for constraints on a particular table_name:
select c.*
from all_constraints c
where c.table_name = 'FOO'
union all
select cs.*
from all_constraints cs
join all_synonyms s
on (s.table_name = cs.table_name
and s.table_owner = cs.owner
and s.synonym_name = 'FOO'
)
HTH
-- addendum:
If your user is granted access to the DBA_ views (e.g. if your user has been granted SELECT_CATALOG_ROLE), you can substitute 'DBA_' in place of 'ALL_' in the preceding SQL examples. The ALL_x views only show objects which you have been granted privileges. The DBA_x views will show all database objects, whether you have privileges on them or not.
I found this question as the top result while Googling how to find the owner of a table in Oracle, so I thought that I would contribute a table specific answer for others' convenience.
To find the owner of a specific table in an Oracle DB, use the following query:
select owner from ALL_TABLES where TABLE_NAME ='<MY-TABLE-NAME>';
Interesting question - I don't think there's any Oracle function that does this (almost like a "which" command in Unix), but you can get the resolution order for the name by:
select * from
(
select object_name objname, object_type, 'my object' details, 1 resolveOrder
from user_objects
where object_type not like 'SYNONYM'
union all
select synonym_name obj , 'my synonym', table_owner||'.'||table_name, 2 resolveOrder
from user_synonyms
union all
select synonym_name obj , 'public synonym', table_owner||'.'||table_name, 3 resolveOrder
from all_synonyms where owner = 'PUBLIC'
)
where objname like upper('&objOfInterest')
Oracle views like ALL_TABLES and ALL_CONSTRAINTS have an owner column, which you can use to restrict your query. There are also variants of these tables beginning with USER instead of ALL, which only list objects which can be accessed by the current user.
One of these views should help to solve your problem. They always worked fine for me for similar problems.
To find the name of the current user within an Oracle session, use the USER function.
Note that the owner of the constraint, the owner of the table containing the foreign key, and the owner of the referenced table may all be different. It sounds like it’s the table owner you’re interested in, in which case this should be close to what you want:
select Constraint_Name
from All_Constraints
where Table_Name = 'WHICHEVER_TABLE'
and Constraint_Type = 'R' and Owner = User;
It is like #entpnerd said, but I suggest you to use upper() clause:
select *
from ALL_TABLES
where upper(TABLE_NAME) = upper('<table_name>')