StringBuilder in .Net

There are small small things which can improve the performance of the code. When we are dynamically constructing SQL query in .Net application we declare a string variable and append the SQL to it.

Ex:

String sSQL = null;
sSQL += "SELECT Col1,Col2,Col3";
sSQL += " FROM Table_name ";
sSQL += " WHERE Col4 = 10 ";

This is not a good approach to deal with String because String is immutable. Therefore, every time when you concatenate the new value a new instance will be made and it will make a great performance loss if concatenation will be done many times.

Lets look at the best apporach

System.Text.StringBuilder sSQL = new System.Text.StringBuilder();
sSQL.Append(" SELECT Col1,Col2,Col3 ");
sSQL.Append(" FROM Table_name ");
sSQL.Append(" WHERE Col4 = 10 ");

So from now on try to use StringBuilder.