I have installed Oracle Database 11g Release 2 (11.2.0.1.0) for Microsoft Windows (x64). How do I create a new schema or local schema?
A schema is the collection of objects owned by a user.
So connect as a power user like SYSTEM and run a create user command. Find out more.
Once you have a user you can connect to it and create tables and other objects.
Have you tried looking in the docs? https://docs.oracle.com/cd/E11882_01/server.112/e41084/statements_6014.htm#SQLRF01313
In oracle a 'schema' is nothing more than the collection of objects belonging to a given user. Many people will even argue that a "user" is a "schema". I believe that it was with 11g (now out of support) that oracle introduced the CREATE SCHEMA command. That command simply combines creating a user and creating some tables belonging to that user into a single SQL statement. You can always do it the "old fashioned" way by simply issuing a CREATE USER, then issuing whatever CREATE . statements you need:
create user fubar identified by fubar;
create table fubar.mytable (dob date);
create view fubar.myview as (select * from fubar.mytable);
etc. etc.
Related
I am creating a new .NET Core 3.1.3 application, connecting to a new SQL Server 2016 database. The connection is a trusted connection. The EF migration tool is creating the tables with me as the owner.
dotnet ef migrations add InitialDb
dotnet ef database update
I don't want that. I want the tables to be owned by a service id that we have created for the purpose. What is the safest and most efficient way to default table creation to that owner?
If you don't specify a schema for your Entities, EF will generate the DDL with no schema specified. And in SQL Server this means that the object will be created in the user's default schema. Normally the user's default schema should be dbo, but if it's not, then the object will be created in a different schema.
And in SQL Server objects are owned (again by default) by the owner of the schema in which they are created.
So, configure the tables to be created in the dbo schema, or configure your user's default schema to be dbo, and the objects will be created in the dbo schema and owned by dbo.
eg in OnModelCreating, add
foreach (var et in modelBuilder.Model.GetEntityTypes())
{
et.SetSchema("dbo");
}
or in SQL
alter user [yourdomain\youruser] with default_schema=dbo
Note that if you are the database owner, or a sysadmin, you always connect to the database as dbo, and your unqualified DDL will create objects in the dbo schema.
I want the tables to be owned by a service id
You don't normally want objects owned by the identity that the application uses to connect, as that identity should be in a role with least-privileges. EG no ability to drop tables or create triggers. Typically the objects should simply be owned by dbo.
At least as of EF Core 6 you can be more succinct with
modelBuilder.HasDefaultSchema("dbo");
Note that if you are using the built-in history table you will need to place extra code in the onConfiguring. Something like
optionsBuilder.UseSqlServer(x => x.MigrationsHistoryTable("__EFMigrationsHistory", "dbo"));
Use case:
I have a web app which drops and recreates a test database on every test run. I'd like to have it do this with a PG role which is not a superuser, and not one which can destroy or create any database willy nilly, but rather, just be allowed to drop and create a specific database name, such as foo_test. Is this possible?
You could create a function with the "SECURITY DEFINER" option that creates the database and sets permissions on it. It would need to be in a database the restricted role could connect to of course.
http://www.postgresql.org/docs/9.1/static/sql-createfunction.html
You might be able to do it all with an SQL function, but it's trivial with plpgsql.
Is it possible to set up a default set of role mappings for Microsoft SQL Server (2008 R2 for instance) that apply to subsequent databases?
Example: Whenever I create a new database on the server, I want it to map db_owner to a login group called Group_A and db_datareader to a group called Group_B.
The databases are created by a 3rd party application, so doing it in the CREATE statement is not enough. What I hope for is to set a default behaviour for the server itself.
Every new database is created as a copy of the model database on the SQL server. So when you do the mapping the the MODEL db every new DB should replicate that. I haven't tried that with roles and groups but you can try it and let me know whether it works...
I have a schema define in my database. Except now everytime I do a sql statement I have to provide the schema ...
SELECT * FROM [myschema].table
I set the default schema for my user using management studio and also ran the
ALTER USER myUser WITH DEFAULT_SCHEMA [myschema]
and I still get the invalid object 'table' when writing a query without the schema (SELECT * FROM table)
Is there a way to write SELECT * FROM table without having to specify the schema name all the time?
It's on SQL 2005 using SQL Management Studio.
Is the user an SA, if so it will not work, according to the documentation SA users are always defaulted to the dbo schema.
The value of DEFAULT_SCHEMA is ignored
if the user is a member of the
sysadmin fixed server role. All
members of the sysadmin fixed server
role have a default schema of dbo.
Couple of options:
Is your user listed under Security > Users (in SSMS)? Check the Properties (right click the name), and see if the Default schema is set in the context of the database, rather than the instance (which is what ALTER USER is setting).
Create a synonym for the table you want to reference:
CREATE SYNONYM table_name
FOR [your_db].[your_schema].table_name
...which will affect everyone who doesn't use at least two name notation, in the context of that database. Read more about it here. But it is associated ultimately to a schema.
Check that the database selected in the "Available Databases" drop down (upper left, to the left of the Execute button) is correct.
Use three name notation when specifying table (and view) references:
SELECT *
FROM [your_db].[your_schema].table_name
If you do not want to use "full qualified" SQl names, then you need to avoid creating your tables using any account or role that's not using the "dbo" default schema assigned. Why do you need to change the default schema on the user if you don't plan on using it?
I have a SQL Server 2008 instance with several databases and I'm currently writing a C# application to access those databases. In this app, the end user can select a database they want to connect to.
I already have a list of all databases on the server, how can I limit that list to those databases the user can log in to? Or, how can I query that list?
There's a lot of databases, but each user can only access some of them, so trying to connect and catching the Exception is probably not a good idea.
Fyi: The server is configured for Windows authentication only, and the logins to the server are created for Windows' user groups (not individual users).
You can query all databases from sys.sysdatabases, and check if the user has access with HAS_DBACCESS:
SELECT name
FROM sys.sysdatabases
WHERE HAS_DBACCESS(name) = 1
Maybe as an alternative to Andomars answer (which I like!) you could interrogate Active Directory to see if the user is a member of a valid group for your database. I suspect this would mean you would have to maintain some Windows Group to Database Name lookup.
You can use the system stored procedure sp_helplogins 'User Name'