Is there a way to declare a schema spanning datasource configuration within wildfly, so that the underlying database (MariaDB in this case) may consist out of n-different schemas (all with the same structure), each accessible through the defined datasource?
I am thinking about some wildcard configuration within the connection-url for the datasource names.
The goal is to achieve a separation of the data between multiple instances of our database schema, each for one customer in one schema.
We have come to a solution to achieve this behaviour.
We have configured a default schema every instance connects to initially. Internally, whenever a new request is received, we have an aspect that issues a use Schemaname to select the correct schema.
Related
I want to query in ssms but I always have to add the specific schema as a prefix, although I have ran the query:
USE (the specific db I wanna use);
GO
What should I do for ssms to bring back only tables from the specific db and schemas while querying?
Within SQL Server, you use the Fully Qualified Name. That consists of three parts (though technically, when using a linked server, you could add a servername part as well):
Database
Schema
Table
And can be used in the following manner:
SELECT * FROM <database>.<schema>.<table>
The USE keyword simply changes the context in which you are executing a SQL command. It's identical to using the drop-down box in SSMS to change to a different database.
By switching the database context, you can typically skip the part of the query above. By switching context, it is assumed all commands will be executed within the database you changed to.
The reason it's still there is if you want to access objects that physically reside within a different database on the same SQL Server instance.
The schema is just a way to group your tables. The default schema is database owner (dbo). If you omit the schema name, it's assumed the object is in the dbo schema. So the following 2 commands are assumed to be identical:
SELECT * FROM dbo.MyTable
SELECT * FROM MyTable
However, using schemas is a great way to structure your database, as you can logically group related objects within the same schema, and assign permissions accordingly.
From an OLTP perspective, you could have a schema dealing with orders, and one with sales. That way it is easier for people to filter only the objects they are interested in, and for the dba to limit access to schemas to specific departments.
If you work with data warehousing, it's not unusual to see an Extract schema, a Stage schema, and a Fact and Dimension schema.
I would like to be able to store the tracking tables in a different database the original. For a couple of reasons.
I would like to be able to drop it on demand if I change versions of my application.
I would like to have multiple sync scopes separated by user permissioning.
I am sure through the sqlmetadatastore class there is a way, but I have not found it yet.
the sqlmetaadatastore will not help you in any way with what you're trying to achieve. am pretty sure its not in anyway exposed in the database sync providers you're using.
note that the tracking tables are not the only objects Sync Framework provisioning creates, you will have triggers, tracking tables, stored procedures and user defined table types. and you're not supposed to be dropping them separately or even dropping them by yourself, but you should be using the deprovisioning API.
now if you really want to have the tracking tables on a separate db, the provisioning API has a Script method that can generate the SQL statements required to create the Sync Fx objects.
you can alter that to create the tracking tables on another DB, but you have to alter the triggers as well to insert on this other database.
I have an application that needs to query two different DB2 databases for the exact same data. Is there any way to create a view that takes my query, executes it against both databases, combines the results, and send them back to my application?
Yes, sort of. We had to do something similar a few years back because one of our customers split their data across two DB2 instances but still wanted single queries that would get at them both (the reporting tool we were using could only connect to one instance).
From memory, it's a matter of:
turning on federation support (needed for instance-to-instance communication).
creating a wrapper with create wrapper so one DB2 instance knows how to connect to another.
registering the other server with create server.
using create user mapping to set up mapping of credentials between the two instances.
creating an alias in the local instance for the remote table with create nickname.
From there, you would just create your view as something like:
select * from localtable union all select * from nickname;
and you should have rows from both tables.
I'm working on a web-based business application where each customer will need to have their own data (think basecamphq.com type model) For scalability and ease-of-upgrades, I'd prefer to have a single database where each customer gets a filtered version of the data. The problem is how to guarantee that they stay sandboxed to their own data. Trying to enforce it in code seems like a disaster waiting to happen. I know Oracle has a way to append a where clause to every query based on a login id, but does Postgresql have anything similar?
If not, is there a different design pattern I could use (like creating a view of each table for each customer that filters)?
Worse case scenario, what is the performance/memory overhead of having 1000 100M databases vs having a single 1Tb database? I will need to provide backup/restore functionality on a per-customer basis which is dead-simple on a single database but quite a bit trickier if they are sharing the database with other customers.
You might want to look into adding Veil to your PostgreSQL installation.
Schemas plus inherited tables might work for this, create your master table then inherit tables into per-customer schemas which provide a company ID or name field default.
Set the permissions per schema for each customer and set the schema search path per user. Use the same table names in each schema so that the queries remain the same.
what is the difference between creating ordinary tables using 'dbo' and creating tables using schemas.How this schema works & supports the tables
A schema is just a container for DB objects - tables, views etc. It allows you to structure a very large database solution you might have. As a sample, have a look at the newer AdventureWorks sample databases - they have a number of schemata included, like "HumanResources" and so forth.
A schema can be a security boundary, e.g. you can give or deny certain users access to a schema as a whole. A schema can also be used to keep tables with the same name apart, e.g. you could create a "user schema" for each user of your application, and have a "Settings" table in each of them, holding that user's settings, e.g. "Bob.Settings", "Mary.Settings" etc.
In my experience, schemata are not used very often in SQL Server. It's a way to organize your database objects into containers, but unless you have a huge amount of database objects, it's probably something you won't really use much.
dbo is a schema.
See if this helps.
Schema seems to be a way of categorizing objects (tables/stored procs/views etc).
Think of it as a bucket to organize related objects based on functionality.
I am not sure, how logged in SQL user is tied to a specific schema though.