Parameters in ADO.NET SQL Commands
When creating a SQL command that modifies a database, it's common practice to use parameters to provide the specific values to be inserted or updated. This approach helps prevent SQL injection attacks and makes code more readable and maintainable.
One instance where parameters are useful is when adding a record to a database table. Imagine you have a command like the following:
SqlCommand comand = new SqlCommand("INSERT INTO Product_table Values(@Product_Name,@Product_Price,@Product_Profit,@p)", connect);
To specify the actual values for the parameters, you need to add them to the command's Parameters collection. The most straightforward way to do this is by creating a SqlParameter object:
SqlParameter ppar = new SqlParameter(); ppar.ParameterName = "@Product_Name"; ppar.Value = textBox1.Text;
However, this approach has some limitations. Instead, it's recommended to use a more explicit method that specifies the data type of each parameter:
cmd.Parameters.Add("@Product_Name", SqlDbType.NVarChar, ProductNameSizeHere).Value = txtProductName.Text; cmd.Parameters.Add("@Product_Price", SqlDbType.Int).Value = txtProductPrice.Text;
This ensures that the database knows the exact data type of each value and can handle it accordingly.
Remember, it's crucial to avoid using the AddWithValue method for adding parameters. For details on why this is the case, you can refer to the following article: https://blogs.msmvps.com/jcoehoorn/blog/2014/05/12/can-we-stop-using-addwithvalue-already/
Additionally, when inserting data, it's good practice to explicitly specify the column names in the SQL statement, as seen in: https://www.w3schools.com/sql/sql_insert.asp
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