Bind variables are placeholders inside a SQL statement.
When a database receives a SQL statement, it determines if the statement has already been executed and stored in memory.
If the statement does exist in memory, Oracle Database can reuse it and skip the task of parsing and optimizing the statement.
Using bind variables makes the statement reusable with different input values.
The Sql Data Adapter opens a connection only when required and closes it as soon as it has performed its task.
In Lesson 3, we discussed a fully connected mode of operation for interacting with a data source by using the Sql Command object.
In Lesson 4, we learned about how to read data quickly an let go of the connection with the Sql Data Reader.
Using bind variables also improves query performance in the database, eliminates the need for special handling of literal quotation marks in the input, and protects against SQL injection attacks.
In this section, you will add a button that enables client data changes to be saved back to the database.The following section will show you how to test updating, inserting, and deleting the data.