Whenever you use the keyword SHARED, the clause AUTHENTICATED BY is required. The following example creates a fixed user, shared link to database sales, connecting as scott and authenticated as keith:ĪUTHENTICATED BY keith IDENTIFIED BY richards |ĪUTHENTICATED BY schema_name IDENTIFIED BY password To create a shared database link, use the keyword SHARED in the CREATE DATABASE LINK statement: Typically, shared links are used for public database links, but can also be used for private database links when many clients access the same local schema (and therefore the same private database link). Shared database links lead to more network connections in single -user scenarios, so use shared links only when many users need to use the same link. Because the user can use each shared server process, each process can establish a connection to the remote server.Ĭlearly, a nonshared database link is preferable in this situation because it requires only one network connection. If this user defines a shared database link and 10 shared server processes exist in the local database, then this user can require up to 10 network connections to the remote server. Assume that only one user accesses the remote server. Shared database links are not useful in all situations. The following table illustrates three possible configurations involving database links:
A simple guideline is to use shared database links when the number of users accessing a database link is expected to be much larger than the number of server processes in the local database. Look carefully at your application and shared server configuration to determine whether to use shared links. Determining Whether to Use Shared Database Linksĭetermining Whether to Use Shared Database Links.This section contains the following topics: Shared database links enable you to limit the number of network connections required between the local server and the remote server. Many users running applications simultaneously can cause a high number of connections between the local and remote databases. Every application that references a remote server using a standard database link establishes a connection between the local database and the remote database.
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