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3 – Schema Architecture StrategiesFigure 3-11: Foreign key to a table on a linked server.We'll allow only the interface with the credit bureau to write data and the usersthat gain access to this linked server will be carefully defined and granted onlyread permissions. Therefore, through the use of linked servers the credit reportdetails in our sample database are stored securely in a server that is dedicated tothat sensitive data. Its reference to any borrower information that would beidentifiable is through a foreign key that is stored in our primary server,referenced inFigure 3-11 as SERVER1\SQLINSTANCEA.Linked servers are implemented using the sp_addlinkedserver system storedprocedure, the syntax of which is as follows:sp_addlinkedserver [Server Name],[Product Name],[Provider Name],[Data Source],[Location],[Provider String],[Catalog]This system stored procedure's arguments are as follows:• Server Name: The textual reference to the linked server that is beingadded. If using the native SQL Server OLE DB provider the server andinstance name of the target database is the value that should beentered.• Product Name: A descriptor of the database product that is beingconnected. For example: "SQL Server" or "Oracle".• Provider Name: The unique programmatic identifier of the OLEDB provider that is being used. This can be obtained using theprovider name value from the results of executing the extended storedprocedure xp_enum_oledb_providers. If this argument isomitted, it will default to the native SQL Server OLE DB provider.79