is Microsoft.Practices.EnterpriseLibrary.Data.Database.SetParameterValue thread safe?

I'm using a Database to run some queries and was thinking to optimize stuff up.

I am basically doing two static objects:

private static Database db = ... ;
private static开发者_如何学JAVA DbCommand cmd = db.GetSqlStringCommand("... where col = @colParam");
....
cmd.Prepare(); //one call

And then was thinking to just do:

db.AddInParameter(cmd, "colParam", DbType.String, "some value on each call")

when calling it.

It only works one time. After the first call I receive

Variable names must be unique within a query batch or stored procedure

an error message regarding @colParam parameter.

So I was then thinking in replacing the add with a set at each call:

db.SetParameterValue(cmd, "colParam", "some value on each call")

But is this safe? I have this feeling...??!?!?!?.

Is it thread safe to have just one command object on which I set the value on each call? What if two users set the value at the same time? What happens then?

This is definitely in the premature optimisation bucket. I am not sure what you think you are optomising.

Your real questions should be is DbCommand thread safe. The answer is no. From the documenation on DbCommand http://msdn.microsoft.com/en-us/library/system.data.common.dbcommand.aspx.

Any instance members are not guaranteed to be thread safe.