We created several views postgresql 12 (not materialized views) which include nested queries and multiple joins.
we are facing a strange behavior, are noticing that some views are disappearing from the view list and others are remaining. is this related to Database configuration.
Are we missing some configuration?
I can only guess, but the one way that views can disappear is if you DROP them. You'd probably remember if you dropped them directly, but you can drop them indirectly with
DROP TABLE some_table CASCADE;
If you do that, all views and materialized views that depend on that table are dropped as well.
We didn't drop the tables directly, however since we are using ESRI ArcGIS Desktop to manage our GIS data which is hosted on a PostgreSQL database. we identified the cause of the issue after the admin replaced all the tables in the schema. and ArcGIS Desktop dropped the tables and deleting the views without informing the admin.
Related
I am using oracle database for a web application.
Is there a table inside system database that records any or all changes that occur inside the database?
For example, if I insert a row or update a row, it would record this change inside a table.
Does this kind of table exist inside oracle database?
In mysql there is INFORMATION_SCHEMA TABLES that records everything that occurs inside the database.
Oracle too provides auditing mechanisms for your DB however, the subject is very extensive to be treated in a simple answer, since control can go down to a very fine grained auditing. Take a look at Oracle Documentation on this theme, good luck.
Using SSDT in VS2012 I have created a number of synonyms from a reporting db to a transactional db.
When viewing the schema view - the synonyms appear under the tables subdir, with the SQLCMD variables as part of the table name.
I can kind-of understand the logic of this, however it does pollute the layout and makes it harder to find the tables I'm looking for?
nb. I cant expand any of these tables (ie they dont show the columns of the synonym) and there is no option to delete (right click only gives Refresh and properties)
Hmmm... Looking further at this it seems there are more issues with the schema view. The image below shows the views of the reference database. (there is no actual reference to these views in the database itself) - it also shows the views of the Master Database (which is also a db reference in the project?)
I’m after a bit of advice on the best way to go about this is SQL server 2008R2 express. I have a number of applications that are in separate databases on the same server. They are all “plugins” that use a central staff/structure list that will be in a separate database. The application is in the process of being migrated from JET.
What I’m looking for is the best way of all the “plugin” databases being able to see the central database and use those tables in standard queries and views etc.
As I’m using express that rules out any replication solution and so far the only option I can think of is to use triggers or a stored procedure to “push” out all the changes to the plugins. The information needs to be populated on a near enough real time basis however the number of changes will be very small maybe up to 100 a day and the biggest table only has about 1000 rows at the moment (the staff names table).
Hopefully that will cover all everything but if anyone needs any more details then just ask
Thanks
Apologies if I've misunderstood, but from your description it sounds like all these databases are hosted on the same instance of SQL Server - it's your mention of replication that makes me uncertain.
Assuming that's the case, you should be able to replace any copies of tables from the central database which are held in the "plugin" databases with views or synonyms which reference the central tables directly, since SQL server allows you to make references between databases on the same server using three-part naming (database_name.schema_name.object_name)
For example, if each plugin db has a table StaffNames, you could replace this with a view by dropping the table, then creating a view:
drop table StaffNames
go
create view StaffNames
as
select * from <centraldbname>.<schema - probably dbo>.StaffNames
go
and your code should continue to work seamlessly, as long as permissions are set up.
Alternatively, you could replace all the references to the shared tables in the plugin databases with three-part name references to the central database, but the view method requires less work.
I have an in house app that has both a Web Interface and a Desktop Interface(is an OCA using Merge Replication). We are still using SQL 2005 and have many 'Archive' tables set up. These are filled by Triggers on there relating Table. tblPersonArchive for tblPerson, etc. To keep the Replication Sets as small as possible I would like to exclude ALL of the Archive tables from replicating.
This shouldn't be an issue from a Business standpoint as that data is never accessed directly by the user's. There is literally no need for it to exist on the Desktop app that is using replication.
What I am trying to figure out, then, is how I accomplish that. My "guess" is that I set the Publication Properties --> Article Properties --> Copy User Triggers = FALSE and then exclude the Archive Tables from the Replication Set. Theoretically the Triggers will still fire, and thus still maintain, the Archive tables through the Web App and on Replication.
Unfortunately, this is only a guess at this point and I was hoping for a little reassurance before plowing in.
Could you not accomplish Publisher only triggers by using the NOT FOR REPLICATION clause in the trigger creation?
We are in the process of a multi-year project where we're building a new system and a new database to eventually replace the old system and database. The users are using the new and old systems as we're changing them.
The problem we keep running into is when an object in one system is dependent on an object in the other system. We've been using views, but have run into a limitation with one of the technologies (Entity Framework) and are considering other options.
The other option we're looking at right now is replication. My boss isn't excited about the extra maintenance that would cause. So, what other options are there for getting dependent data into the database that needs it?
Update:
The technologies we're using are SQL Server 2008 and Entity Framework. Both databases are within the same sql server instance so linked servers shouldn't be necessary.
The limitation we're facing with Entity Framework is we can't seem to create the relationships between the table-based-entities and the view-based-entities. No relationship can exist in the database between a view and a table, as far as I know, so the edmx diagram can't infer it. And I cannot seem to create the relationship manually without getting errors. It thinks all columns in the view are keys.
If I leave it that way I get an error like this for each column in the view:
Association End key property [...] is
not mapped.
If I try to change the "Entity Key" property to false on the columns that are not the key I get this error:
All the key properties of the
EntitySet [...] must be mapped to all
the key properties [...] of table
viewName.
According to this forum post it sounds like a limitation of the Entity Framework.
Update #2
I should also mention the main limitation of the Entity Framework is that it only supports one database at a time. So we need the old data to appear to be in the new database for the Entity Framework to see it. We only need read access of the old system data in the new system.
You can use linked server queries to leave the data where it is, but connect to it from the other db.
Depending on how up-to-date the data in each db needs to be & if one data source can remain read-only you can:
Use the Database Copy Wizard to create an SSIS package
that you can run periodically as a SQL Agent Task
Use snapshot replication
Create a custom BCP in/out process
to get the data to the other db
Use transactional replication, which
can be near-realtime.
If data needs to be read-write in both database then you can use:
transactional replication with
update subscriptions
merge replication
As you go down the list the amount of work involved in maintaining the solution increases. Using linked server queries will work best if its the right fit for what you're trying to achieve.
EDIT: If they're the same server then as suggested by another user you should be able to access the table with servername.databasename.schema.tablename Looks like it's an entity-framework issues & not a db issue.
I don't know about EntityToSql but I know in LinqToSql you can connect to multiple databases/servers in one .dbml if you prefix the tables with:
ServerName.DatabaseName.SchemaName.TableName
MyServer.MyOldDatabase.dbo.Customers
I have been able to click on a table in the .dbml and copy and paste it into the .dbml of the alternate project prefix the name and set up the relationships and it works... like I said this was in LinqToSql, though have not tried it with EntityToSql. I would give it shot before you go though all the work of replication and such.
If Linq-to-Entities cannot cross DB's then Replication or something that emulates it is the only thing that will work.
For performance purposes you probably want either Merge replication or Transactional with queued (not immediate) updating.
Thanks for the responses. We're going to try adding triggers to the old database tables to insert/update/delete records in the new tables of the new database. This way we can continue to use Entity Framework and also do any data transformations we need.
Once the UI functions move over to the new system for a particular feature, we'll remove the table from the old database and add a view to the old database with the same name that points to the new database table for backwards compatibility.
One thing that I realized needs to happen before we can do this is we have to search all our code and sql for ##Identity and replace it with scope_identity() so the triggers don't mess up the Ids in the old system.