ADO.NET Data Access Best Practices

ADO.NET Command Execution Best Practices

Efficient and secure execution of commands is crucial for any data-driven application. This section outlines best practices for using ADO.NET commands to interact with your data sources.

1. Use Parameterized Queries

Always use parameterized queries to prevent SQL injection vulnerabilities and improve performance by allowing the database to cache execution plans. Avoid concatenating user input directly into SQL strings.

using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();
    string sql = "SELECT * FROM Products WHERE Category = @Category AND Price > @MinPrice";
    using (SqlCommand command = new SqlCommand(sql, connection))
    {
        command.Parameters.AddWithValue("@Category", "Electronics");
        command.Parameters.AddWithValue("@MinPrice", 100.00);

        using (SqlDataReader reader = command.ExecuteReader())
        {
            // Process results
        }
    }
}
            

2. Properly Manage Command Objects

Ensure that SqlCommand objects are disposed of properly when no longer needed to release resources. The using statement is the recommended approach.

// The 'using' statement automatically calls Dispose()
using (SqlCommand command = new SqlCommand(sql, connection))
{
    // ...
} // command is disposed here
            

3. Choose the Right Command Type

Set the CommandType property of your SqlCommand object appropriately. Use CommandType.Text for SQL statements, CommandType.StoredProcedure for stored procedures, and CommandType.TableDirect for accessing a single table.

// Executing a stored procedure
using (SqlCommand command = new SqlCommand("usp_GetCustomerOrders", connection))
{
    command.CommandType = CommandType.StoredProcedure;
    command.Parameters.AddWithValue("@CustomerID", customerId);
    // ...
}
            

4. Optimize Stored Procedures

When using stored procedures, ensure they are well-written and optimized within the database. Avoid excessive logic or cursors in stored procedures if they can be handled more efficiently in application code or by SQL.

5. Execute Commands Efficiently

Use the most appropriate Execute... method for your needs:

• ExecuteReader(): For queries that return a result set (e.g., SELECT statements).
• ExecuteNonQuery(): For commands that do not return a result set (e.g., INSERT, UPDATE, DELETE, or executing stored procedures that perform actions).
• ExecuteScalar(): For queries that return a single value (e.g., COUNT(*), MAX()).
• ExecuteXmlReader(): For XML data.

6. Handle Command Timeouts

Set an appropriate CommandTimeout value to prevent long-running queries from blocking your application indefinitely. The default timeout is 30 seconds.

command.CommandTimeout = 60; // Set timeout to 60 seconds
            

7. Limit the Scope of Open Connections

Keep connections open only for the duration necessary to execute commands. The using statement for SqlConnection and SqlCommand helps manage this automatically.

8. Consider Asynchronous Operations

For responsive UI applications, use asynchronous methods like ExecuteReaderAsync(), ExecuteNonQueryAsync(), and ExecuteScalarAsync() to avoid blocking the main thread during database operations.

By adhering to these best practices, you can build more robust, secure, and performant data access layers in your .NET applications.