We are using H2 as test database for junittest suite. The actual application has tables in multiple databases like db1.s1.table1 and db2.s1.table2 (in other words database.schema.tablename) . To replicate that functionality we need to create two databases db1 and db2 and then create schema and tables accordingly. Also we have a dbscript.sql which loads all data before running test suite.
Please let us know if there is a way to create multiple databases in H2. If yes, what will be the exact command to do that as part of the script.
Since H2 creates the database specified as part of jdbc URL. Is there a way to specify multiple databases as part of URL so we can have them created.
Related
I made a custom application that is running from several years and is full of company data.
Now I need to replicate the application for another customer, so I set up a new server then i cloned the databases and empty all the tables.
Then I made a database and file shrink.
On the SQL Server side, the databases looks empty but if I run a grep search on the database files .mdf and .log I still can find recurrence of the previous company name also in system databases.
How do I really clean a SQL Server database?
Don't use backup/restore to clone a database for distribution to different clients. These commands copy data at the physical page/extent level, which may contain artifacts of deleted data, dropped objects, etc.
The best practice for this need is to create a new database with schema and system data from scratch using T-SQL scripts (ideally source controlled). If you don't already have these scripts, T-SQL scripts for schema/data can be generated from an existing database using the SMO API via .NET code or PowerShell. Here's the first answer I found with a search that uses the Microsoft.SqlServer.Management.SMO.Scripter class. Note you can include scripts data too (insert statements) by specifying the ScriptData scripting option for desired tables.
I have two companies using same application running in Oracle Database. Now the companies are merging and making a single company. The databases are huge with an approximate size of 10 TB.
We wanted to have the application in two databases to be merged and have a single application pointed to both the databases with minimal work.
Help is highly appreciated.
Regards
Bjm
Using DB Links feature in Oracle
For more information you can use below link regarding Database Links:
https://docs.oracle.com/cd/B28359_01/server.111/b28310/ds_concepts002.htm#ADMIN12083
It would enable you to build a SQL statement that references tables from the two different databases.
If you want to access the data in instance B from the instance A, you can use below query and edit the details accordingly:
CREATE DATABASE LINK dblink_example
CONNECT TO xxusernamexx IDENTIFIED BY xxpasswordxx
USING
'(DESCRIPTION=
(ADDRESS=
(PROTOCOL=TCP)
(HOST=xxipaddrxx / xxhostxx )
(PORT=xxportxx))
(CONNECT_DATA=
(SID=xxsidxx)))';
Now you can execute the below query to access the table:
SELECT * FROM tablename#dblink_example;
You can perform any operation DML, DDL, DQL using DB Link
I have a requirement that a user can have multiple environments to make experiments and test how good their modifications are; after the users are satisfied with the modifications they've done to the data in the working environment, these modifications can be (partially or completely) copied to another environment; these environments can be created as empty or as copies of other environments; right now we are using SQL Azure and our current (not implemented) approach is creating each environment as a different SQL schema in the same database using the statement
CREATE SCHEMA
till now in POCs this is working really good for us. But what i don't like of this approach is that creating a new schema involves executing several scripts to create the tables and the SPs in the new schema, so as we create or update the default schema objects, we also need to update the scripts that create the schema, also that when the schema is created we need to bulk copy the data from the original schema using another script, so considering the size of the client's data this process sometimes it cannot be not as fast as I would like, and also maintaining the SQL code to create environments is not that good for the team.
so my question is, is there any way to duplicate an entire dbo schema with a different name using T-SQL Statements?, i know this can be done manually using SQL Server Management Studio and the generate scripts option, but this must happen automatically because the users can create a new environment at any time, i already checked the documentation for
ALTER SCHEMA TargetSchema
TRANSFER SourceSchema.TableName;
but this just changes the database object schema, it does not create an actual copy of the object.
EDIT:
I am not trying to create different databases for dev, qa and production, I already have them; what I want to achieve is create a web app with multiple environments, each environment is a sandbox for the final user to make experiments, imagine it is like creating a draft before making this data available for the general public, so when the users are satisfied with the modifications they can move this data to the public environment and then when it is moved, it is available for others to see it
You can use the CREATE DATABASE ... AS COPY OF transact-sql statement to create copies of your Production database that can be used as QA, testing and development databases.
CREATE DATABASE db_copy
AS COPY OF ozabzw7545.db_original ( SERVICE_OBJECTIVE = 'P2') ;
Here ozabzw7545 is the name of Azure SQL Database server.
The following is the full syntax + additional information that is specific to Azure SQL database: CREATE DATABASE (Azure SQL Database)
Additional Information for Copy an Azure SQL database
You also can use PowerShell:
New-AzureRmSqlDatabaseCopy -ResourceGroupName "myResourceGroup" `
-ServerName $sourceserver `
-DatabaseName "MySampleDatabase" `
-CopyResourceGroupName "myResourceGroup" `
-CopyServerName $targetserver `
-CopyDatabaseName "CopyOfMySampleDatabase"
Ive run into the issue where I need to query 2 separate databases(same instance) in one query.
I am used to doing this with mysql, but Im not sure how to do it with DB2.
In mySQL it would be something like:
SELECT user_info.*, game.*
FROM user_info, second_db.game_stats as game
WHERE user_info.uid = game.uid
So the question is how i translate a query like that into DB2 syntax?
Equivalent of this
Is there a reason why you have the tables in a separate database? MySQL doesn't support the concept of schemas, because in MySQL a "schema" is the same thing as a "database". In DB2, a schema is simply a collection of named objects that lets you group them together.
In DB2, a single database is much closer to an entire MySQL server, as each DB2 database can have multiple schemas. With multiple schemas inside the same database, your query can run more or less unchanged from how it is written.
However, if you really have 2 separate DB2 databases (and, for some reason, don't want to migrate to a single database with multiple schemas): You can do this by defining a nickname in your first database.
This requires a somewhat convoluted process of defining a wrapper (CREATE WRAPPER), a server (CREATE SERVER), user mapping(s) (CREATE USER MAPPING) and finally the nickname (CREATE NICKNAME). It is generally easiest to do these tasks using the Control Center GUI because it will walk you through the process of defining each of these.
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.