# Dynamic parameters

You can prepare statements that are allowed to have parameters for which the value is not specified when the statement is prepared using PreparedStatement methods in the JDBC API. These parameters are called dynamic parameters and are represented by a ?.

The JDBC API documents refer to dynamic parameters as IN, INOUT, or OUT parameters. In SQL, they are always IN parameters.

New: Derby supports the interface ParameterMetaData, new in JDBC 3.0. This interface describes the number, type, and properties of prepared statement parameters. See the Java DB Developer's Guide for more information.

You must specify values for them before executing the statement. The values specified must match the types expected.

- Dynamic parameters example
- Where dynamic parameters are allowed

Parent topic: SQL expressions
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