What is Client in SAP ? Explained .

Clients in SAP are logical entities on one or many system (instance). Means there could be one system and that could have multiple clients running on it. Or there could be multiple system running with single client on each system. Confused!!!

To understand it better, a typical environment can have one development server, SIT server, UAT server & production server. When we call them server we mean in general terms these are separate machines having separates OS running and having separate hardware. But in SAP Development ,SIT, UAT and Production server can be on the same system i.e. on single system and all these server named as Client.

Single SAP installation with multiple client

Basically these concepts of having multiple clients (in general terms server) comes from era when single mainframe machines are shared by multiple companies to run their business where each companies share one client.

So in SAP Client shares same hardware same OS and "Same Set of Tables” as well.

“Same Set of Table” how?

Consider a system running two clients on it one is called DEV and other is UAT. Both client can have master data stored on the same table but visible to their own view. They cannot see each other data. This feature of the table is called as client dependent. To make it possible SAP put first column of table as client information. So whichever client try to access data from shared table internally that particular set of rows SAP make visible specific to that client.

There is concept of Client independent table also. Where all client share the same table has the same view of data. A typical example could be Printer Information in a table. That information can be share across all the client DEV,SIT,PROD.