SQL 2012 Standard user CAL's required for vCenter Server 5.1 and VUM

Hello Friends,

In Our organization we are planning to deploy vCenter Server 5.1 and VUM on one server. vCenter and VUM will be accessing two separate Databases created on a SQL Server 2012 Standard. Just need some help in buying SQL 2012 license. We are going with server license. How many user CAL's we need to buy with SQL 2012. Normally CAL's are required for each user accessing a SQL 2012 Database. Can anyone help me with number of user CAL's we need to buy for vCenter and VUM.

Thanks,

Vipil