Database Reference
In-Depth Information
from two diferent federation members. In addition, the applications should not check ref-
erential integrity across multiple federation members.
◾
For scalability, applications should be so designed that they are able to rebalance the work-
load by splitting and merging of federation members.
◾
Applications should be so designed that they are able to propagate structure changes made
in a database object to all other federation members.
In addition to the above design strategies, you may consider using virtual federations to simu-
late physical federations for scalability and lexibility. Also, to ease the diiculties in federation
management, you may consider using a denormalized table that includes data from several related
tables.
8.4.2 Federation Implementation with T-SQL
T-SQL can be used to create a federation root and federations hosted by the federation root. With
T-SQL, database administrators can also create federation members, atomic units, and establish
connections to federations. hey can also manage federations with T-SQL. he following are some
commonly used federation-related SQL statements.
SQL Statement for Creating Federation Root
: Since a federation root is a database that hosts
a set of federations, the SQL statement for creating a federation root is the same as the statement
for creating a database as shown below:
CREATE DATABASE [database_name]
SQL Statement for Creating Federation
: After connecting to a federation root, enter the
following SQL statement:
CREATE FEDERATION
federation_name (distribution_name
<
data_type
>
RANGE)
he above SQL statement is described below:
◾
federation_name
: It is the name of the federation to be created. he name of the federation
should be unique within a federation root.
◾
distribution_name
: It is the name of the federation key. As an identiier, the name should
be unique and is limited to 128 unicode characters.
◾
data_type
: It is the data type for the federation key. he data type can be INT, BIGINT,
UNIQUEIDENTIFIER, or VARBINARY(
n
), where
n
can be a maximum of 900.
◾
R ANGE
: It deines a partition with a range value.
SQL Statement for Altering Federation
: To modify a federation, use the following SQL
statement:
ALTER FEDERATION federation_name
{
SPLIT AT (distribution_name
=
boundary_value)
|DROP AT ([LOW|HIGH] distribution_name
=
boundary_value)
}
