You state that the column is varchar(50)
, but you are using DbType.String
; however, DbType.String
is nvarchar(...)
- i.e. unicode. Now, sometimes the server will do the conversion the "right way around" (where "right" here means: the one that doesn't kill performance), but sometimes it will make the alternative choice (for example, it might decide that it can't use the index and do a table scan, or even worse - it might decide to convert every row in turn for the comparison). The best thing to do, then, is to specify the correct data-type in the first place: by using DbType.AnsiString
. There's nothing "wrong" with either DbType.String
or DbType.AnsiString
- so long as they are correctly being used to represent nvarchar
and varchar
respectively.
Parameter Add Causing Timeout in DBCommand
Domanda
I have a Parameter add function like bellow:
public static void AddParameter(DbCommand comm, string ParamName, Object objValue, DbType Paramtype,int paramSize)
{
//comm.Parameters.Clear();
DbParameter param = comm.CreateParameter();
param.ParameterName = ParamName;
param.DbType = Paramtype;
param.Size = paramSize;
param.Direction = ParameterDirection.Input;
param.Value = objValue;
comm.Parameters.Add(param);
}
Now when do the following:
conn.Open();
DbCommand cmd = conn.CreateCommand();
cmd.CommandText = "SELECT * FROM tableName WHERE MemberID=@MemberID";
AddParameter(cmd, "@MemberID", "00000970-b1fd-49ad-89fc-1de066c0076c", DbType.String, 50);
cmd.ExecuteReader();
I get Timeout exception. But if I run the same command Like
SELECT * FROM tableName WHERE MemberID='00000970-b1fd-49ad-89fc-1de066c0076c'
I get my desired output... Can anybody help me find out where is my problem? conn
here is a SqlConnection.
Thanks.
Soluzione
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