I have to run a script for a company. I just get the same error every time.
The query:
DELETE FROM WMO
WHERE (clientnr = ****** AND number_message = *****)
The error:
ORA-01752: cannot delete from view without exactly one key-preserved
table
What did I wrong?
Thnx!
Database views are in general projection of one or more tables. It is a SELECT statement over one or more tables to be specific. For database engine it is impossible to decide what it should delete and from which table unless the view is constructed from single table.
The best solution is to run DELETE command against tables that are used to construct the view.
Additional information:
ORA-01752: cannot delete from view without exactly one key-preserved table
Related
I have two different databases. Let's say 'DbOne' and 'DbTwo'.
Is there any way to do the followings?
Create a view in DbOne
Transfer data in a particular table from DbTwo to the newly created view in DbOne.
I am using SSMS and still figuring out the appropriate query..
Please give me any advice.
You need INSERT / SELECT statement - eg.
INSERT INTO DbOne..NewView
SELECT * FROM DbTwo..SourceTable
However, depending on the structure of both tables, you may need to specify the particular columns in the SELECT statement, to match the structure of the target table. (By the way, note that data is always going into a TABLE - not a VIEW. You can do an INSERT into a VIEW, but only under certain conditions)
We have a table in our Oracle Database that was created from an actual script.
Ex:
Create Table AS (Select * from table).
I was hoping to recover the original script the table was created from as the data is quite old in the table, but needs this created table needs to be refreshed. This table is created with data from another live table in our database, so if there is a way to refresh this without the original query - I'm open ears. Any solutions are welcomed!
Thanks!
I suppose you could also do a column by column comparison of this table against all others to see which one (if any) matches it. Of course, this would only be a guess.
It would require that object to actually be a materialized view instead of a table. Otherwise you are probably left off with exploring logs. Beyond that I doubt there is any way to recover the original select statement used to create that table.
I am in a situation where I want to drop a view or table, but can only know at run-time which it is (same identifier though). This does not work:
DROP VIEW IF EXISTS my_table_or_view;
Because if my_table_or_view is a table, it will throw:
android.database.sqlite.SQLiteException: use DROP TABLE to delete table my_table_or_view
Likewise, I cannot use DROP TABLE, because it tells me to use DROP VIEW if i have a view at hand. I could catch the error, of course, but since this is part of a larger transaction, I would definitely prefer an answer that works using pure SQL (as understood by sqlite3). Any ideas?
You can get information about items in your sqlite database by SELECTing from a pseudo-table called sqlite_master.
In this case, you would do:
SELECT type FROM sqlite_master WHERE name = 'my_table_or_view'
and the resulting information will tell you whether you're dealing with a table or a view.
More info: http://www.sqlite.org/faq.html#q7
I have a staging table (stage_enrolments) and a production table (enrolments). The staging table isn't partitioned, the production table is. I'm trying to use the ALTER TABLE SWITCH statement to transfer the records in the staging table to production.
ALTER TABLE dbo.stage_enrolments
SWITCH TO dbo.enrolments PARTITION #partition_num;
However, when I execute this statement I get the following error:
ALTER TABLE SWITCH statement failed. Target table 'Academic.dbo.enrolments' is referenced by 1 indexed view(s), but source table 'Academic.dbo.stage_enrolments' is only referenced by 0 matching indexed view(s)
I have the same indexed view defined on dbo.stage_enrolments as I do on dbo.enrolments - although the view on enrolments is partitioned. I've tried recreating the views and their indexes checking that all options are the same but I get the same result. If I remove the index from the dbo.enrolments view then it works fine.
I have it working on another set of tables that have indexed views so I'm not sure why it isn't working for these. Does anyone have an idea as to why this may be occurring? What else should I check?
The problem has now been sorted. I've recreated the indexed view once again and it is now working. I haven't actually changed anything though other than the name of the index so I'm not sure what the problem was.
In SQL it is possible to run inserts and updates against a view, as long as the view only selects data from one table. However, deletes don't seem to work quite so well. Can anyone help out?
Take this view for example:
CREATE VIEW v_MyUpdatableView
AS
SELECT x.* FROM MyPrimaryTable x
LEFT OUTER JOIN AnotherTable y ON y.MyPrimaryTableId = x.Id
I can run updates and inserts against this view and they happily pass through to MyPrimaryTable.
However, if I run a delete I receive the following exception:
View or function 'v_MyUpdatableView' is not updatable because the modification affects multiple base tables.
Quote:
DELETE statements remove data in one or more of the member tables through the partitioned view. The DELETE statements must adhere to this rule:
DELETE statements are not allowed if there is a self-join with the same view, or any of the member tables.
Data Modification Rules - Creating a Partitioned View
I would just create a stored procedure that would delete the data from two tables. I know it's not pretty, but it would work or do logical deletes, where you update a column to be "deleted".