I'm converting database from Teradata to SqlServer. I've noticed all tables and procedures are named by the prefix "dbo." (e.g. "dbo.Table1").
I would like to know if and how I can get rid of "dbo" because it would make the conversion task a lot more easier.
dbo is not part of the table name. It is the name of the schema that the tables and stored procedures are attached to. dbo is the default schema in SQL server, though you can add others if needed.
See this MSDN article about them.
dbo is the schema, you can specify a new schema if you like. dbo is default is sql server.
All tables have to go into a schema. As durilai says, dbo is the "default" schema for SQL Server (it always exists). However, note that different users can have different default schemas (if more than one exists).
If you make reference to a table without specifying the schema, then SQL Server will search in your default schema for it (and the same goes for any other objects).
So, if your default schema is dbo, the following two statements are equivalent:
select * from Table1
select * from dbo.Table1
dbo is the default schema in SQL Server if no schema was set by user,
if you want you can create new schema and create tables to it.
Schemas are useful. For example, I used to grant an app login execute permission to every stored procedure separately. Now I grant the app login execute permission to the schema that contains all the stored procedures. This is much easier.
Related
I named my tables as Employee and Department whereas in MSSMS it is displayed as dbo.Employee and dbo.Department respectively and the query works if I use either of them, Why is it so?
dbo schema is the default schema when you create tables, views and etc in SQL Server.
When you create a table it will be placed in default schema and you can call it like dbo.tableName or just tableName.
Schemas
SQL Server ships with ten pre-defined schemas that have the same names as the built-in database users and roles. These exist mainly for backward compatibility. You can drop the schemas that have the same names as the fixed database roles if you do not need them.
You cannot drop the following schemas:
Default schemas :
dbo
guest
sys
INFORMATION_SCHEMA
For more info see : Microsoft SQL Server schemas
You can create your schemas to allow you to better manage your objects too.
dbo is a so-called schema. This is similar to a folder.
Every table, view, procedure, etc. is always put into a schema.
But if you don't specify the schema, then dbo is used.
I am new to SQL Server. I connected to SQL server via SQuirrel Client.
Connection URL:
jdbc:sqlserver://192.xx.xx.xx:1433;databaseName=ep
with username & password.
Then I tried a query on table1 in schema1 -
SELECT * from table1
It returned records. I did not mention schema name in query.
There may be possibility of having tables in different sachems (same database) with same name.
Am I right? If yes, then how will it resolve schema name?
Schema work like a namespace in SQL SERVER, you can create tables, views, sps under a schema and set GRANT, DENY, or REVOKE permissions on those objects. From Implementation of Database Object Schemas
SQL Server 2005 implemented the concept of a database object schema. A schema is a distinct namespace to facilitate the separation, management, and ownership of database objects. It removed the tight coupling of database objects and owners to improve the security administration of database objects. Database object schemas offer functionality to control and help secure application objects within a database environment not available in previous versions of SQL Server.
Just wanted to add here, if you have not specified any schema than, it select dbo as schema.
It is distinguished by its owner. Every object (table ,view ,proc) has an owner which must be a user in the database. For example you may have user1.table1 and user2.table2 in the same database.
So you may type
select * from user1.table1
and
select * from user2.table1
You may see names like dbo.table_name, this means that the owner is the dbo, the database owner. If you do not specify an owner then the system checks dbo and your user (the user that run the command)
I've been using LinqPad for a while now, but have only noticed this problem recently. We have some stored procedures in our DB that have a schema other than dbo, such as [admin].[ClearTransientData].
When I connect to that database with LinqPad, it will only show the stored procedures with the [dbo] schema.
The schema in question is owned by the dbo role and I'm connecting to the database with an account in the dbo role. When I connect to the same database with SSMS using the same account, I can see all of the sprocs no matter the schema.
Am I missing something in the connection definition?
I found the answer, thanks to a prompting from the mobile stackexchange app. I cannot find the user that contacted me (if it was you, please add a comment to the question above or post an answer so I can mark it correct).
Anyway, the default grouping in Linqpad is:
Schema
Tables (only nested in the default schema)
Functions
Stored Procs
Views
However, for the default schema (dbo in this case), that grouping is left out, so 'Tables', 'Functions', 'Stored Procs' and 'Views' appear at the top level. This led me to believe that all stored procedures would be grouped at the top 'Stored Procs' level, then sub-grouped by shcema name under that. This is not the case.
All I had to do was expand the 'Admin' schema[1] in the tree and there was the 'Stored Procs' grouping I was looking for.
Admin
Table1
Table2
Stored Procs
proc1
proc2
Thanks,
Mark
[1] the name of the schema in question actually begins with 'V', which placed deep in the tree view. Since I'm lazy and had to scroll down to see it, I didn't see it right away.
I've been trying to figure out why SQL Server has db_owner schema and db_owner role? This is very confusing. I've been searching for answers and so far this is how my understanding goes:
All tables and objects (such as constraints etc) belong to a schema. DBO being the default schema.
A user may be given permission to edit each object or the schema. A permission on the schema extends the permission to all objects within that schema. So you don't have to grant permission on each individual object.
A role groups permissions together for convenience.
If any of this is incorrect let me know. But I think so far so good. Now my questions are:
What exactly is db_owner schema as seen in "Database User" dialog box of SQL Server Management Studio? And on the same dialog, you define the "Default Schema" as dbo. Why aren't the two the same? If by default SQL Server uses dbo to create all objects under, what use is db_owner?
Why would a user want to own a schema? You are assigning permissions/roles already. What does owning db_accessadmin give you?
Can you give an example of when you create objects under db_owner schema and db_accessadmin schema? In other words does anyone legitimately use those schemas?
A SQL Server schema is simply container of objects, such as tables, stored procedures, etc. A Database Role is a group of principals, such as windows logins, sql server users, etc.
The idea is you can have a role of say "IT", and have all IT users under that role. Then you have can a schema called "IT", and have all tables that belong to IT under that. Out of the box SQL Server creates matching schemas for each default user and role in the database, but I think the intention is you customize this to match the needs of your organization.
This article has more information on the differences between owners and schemas. This question on Stack Overflow may also be useful.
I am quoting the below from the following link.
https://msdn.microsoft.com/en-us/library/bb669061(v=vs.110).aspx
SQL Server ships with ten pre-defined schemas that have the same names as the built-in database users and roles. These exist mainly for backward compatibility. You can drop the schemas that have the same names as the fixed database roles if you do not need them. You cannot drop the following schemas:
dbo
guest
sys
INFORMATION_SCHEMA
At least on my local instance, when I create tables, they are all prefixed with "dbo.". Why is that?
dbo is the default schema in SQL Server. You can create your own schemas to allow you to better manage your object namespace.
If you are using Sql Server Management Studio, you can create your own schema by browsing to Databases - Your Database - Security - Schemas.
To create one using a script is as easy as (for example):
CREATE SCHEMA [EnterSchemaNameHere] AUTHORIZATION [dbo]
You can use them to logically group your tables, for example by creating a schema for "Financial" information and another for "Personal" data. Your tables would then display as:
Financial.BankAccounts
Financial.Transactions
Personal.Address
Rather than using the default schema of dbo.
It's new to SQL 2005 and offers a simplified way to group objects, especially for the purpose of securing the objects in that "group".
The following link offers a more in depth explanation as to what it is, why we would use it:
Understanding the Difference between Owners and Schemas in SQL Server
Microsoft introduced schema in version 2005. For those who didn’t know about schema, and those who didn’t care, objects were put into a default schema dbo.
dbo stands for DataBase Owner, but that’s not really important.
Think of a schema as you would a folder for files:
You don’t need to refer to the schema if the object is in the same or default schema
You can reference an object in a different schema by using the schema as a prefix, the way you can reference a file in a different folder.
You can’t have two objects with the same name in a single schema, but you can in different schema
Using schema can help you to organise a larger number of objects
Schema can also be assigned to particular users and roles, so you can control access to who can do what.
You can generally access any object from any schema. However, it is possible to control which users have which access to particular schema, so you can use schema in your security model.
Because dbo is the default, you normally don’t need to specify it within a single database:
SELECT * FROM customers;
SELECT * FROM dbo.customers;
mean the same thing.
I am inclined to disagree with the notion of always using the dbo. prefix, since the more you clutter your code with unnecessary detail, the harder it is to read and manage.
For the most part, you can ignore the schema. However, the schema will make itself apparent in the following situations:
If you view the tables in either the object navigator or in an external application, such as Microsoft Excel or Access, you will see the dbo. prefix. You can still ignore it.
If you reference a table in another database, you will need its full name in the form database.schema.table:
SELECT * FROM bookshop.dbo.customers;
For historical reasons, if you write a user defined scalar function, you will need to call it with the schema prefix:
CREATE FUNCTION tax(#amount DECIMAL(6,2) RETURNS DECIMAL(6,2) AS
BEGIN
RETURN #amount * 0.1;
END;
GO
SELECT total, dbo.tax(total) FROM pricelist;
This does not apply to other objects, such as table functions, procedures and views.
You can use schema to overcome naming conflicts. For example, if every user has a personal schema, they can create additional objects without having to fight with other users over the name.
Something from Microsoft (Documentation)
The dbo user is a special user principal in each database. All SQL Server administrators, members of the sysadmin fixed server role, sa login, and owners of the database, enter databases as the dbo user. The dbo user has all permissions in the database and cannot be limited or dropped. dbo stands for database owner, but the dbouser account is not the same as the db_owner fixed database role, and the db_owner fixed database role is not the same as the user account that is recorded as the owner of the database.
The dbo user owns the dbo schema. The dbo schema is the default schema for all users, unless some other schema is specified. The dbo schema cannot be dropped.
The dbo user owns the dbo schema. The dbo schema is the default schema for all users, unless some other schema is specified. The dbo schema cannot be dropped.
DBO is the default schema in SQL Server. You can create your own schemas to allow you to better manage your object namespace. As a best practice, I always add the "DBO." prefix even though it is not necessary. Most of the time in SQL it's good to be explicit.