How many keys can be created on a Table ??
Key can have 16 fields and should not exceed 252 Bytes in SQL.
Maximum 40 Keys on a table.
Give careful thought to why you would need so many indexes. Remember they are a double-edged sword. While keys can improve data access (read performance) the trade-off is a negative impact to write performance. The goal is to decide the right balance for your system.
Please detail it’s negative impact, as many keys are created on table according to report’s requirements.
Does it impact indexes ?
Keys are Indexes and of course it will impact your DB performance.
No that is not true.
A key in the NAV table designer is a sort order. you must have a key in order to be able to sort in NAV.
An index in SQL Server is also a sort order, but it is mostly used by SQL Server to be more efficient at retrieving records from the database.
By default, when you create a key in the NAV table designer, it creates an index for the same fields (plus the primary key fields to make the index unique). You can completely disable the SQL Server index by unchecking the MaintainSQLIndex property of the key. You can modify the SQL Server index by specifying the fields in the SQLIndex property (which is not recommended for version 5.0 SP1 and higher).
A key is most definitely NOT the same thing as an index.