preparedStatement

A PreparedStatement is an interface in Java Database Connectivity (JDBC) that represents a precompiled SQL statement. This means the SQL statement is sent to the database for compilation once, and then can be executed multiple times with different parameter values. This precompilation process offers several advantages, primarily in terms of performance and security.

The primary benefit of using PreparedStatement is improved performance, especially when executing the same SQL query repeatedly. By compiling the statement once, the database avoids the overhead of parsing and optimizing the query each time it's executed. This can lead to significant speedups in applications that perform many similar database operations.

Another crucial advantage of PreparedStatement is its role in preventing SQL injection attacks. SQL injection is a security vulnerability where malicious SQL code is inserted into data input fields, which can then be executed by the database. PreparedStatement handles parameter substitution in a way that treats all input values as literal data, not executable code. This ensures that any user-provided input is safely passed to the database without being interpreted as part of the SQL command.

To use a PreparedStatement, you first create it using a connection object, providing the SQL query with placeholders for parameters (indicated by question marks). Then, you set the values for these parameters using the `setXXX()` methods, where XXX corresponds to the data type of the parameter. Finally, you execute the statement. For example, `preparedStatement.setInt(1, userId)` would set the first parameter to an integer value.