I may need clarification on your question, but here is my answer to what I think you are asking:
The BMTM Server uses a database heavily. BMM uses this database for many purposes, but the two most important are storing the monitored objects and their relationships in tables like QP_NODES and QP_TYPEDEFS and then storing the historical values of monitored attributes in tables like QP_HDHR and QP_HDLR for trending and reporting purposes. There is exactly one BMM database per BMTM Server, but it must be supplied by the customer and is external to BMM itself. DB2, Oracle, and SQL Server are the supported database providers. A customer should choose whichever they can most comfortably administer. The database should be dedicated to BMM, perform well, and be close to the BMTM Server in network terms (i.e. a ping response time of a few ms at most).
I hope that answers your question.
Really Helpul Info.
As per the comment :--
"There is exactly one BMM database per BMTM Server "
In my scenario , the query is
this database should be on a separate server or a dedicated database instance (a server with a multiple MSSQL instances for different tools) , will work ( if the resources on the server are enough)
A dedicated instance is not required. If you have one, that is great. Just remember that BMM is a little unusual for database usage because it does a large number of updates when keeping historical records. Thus, disk speed is important for the database system. Most important is that the database be close to the BMM Server in the network.