javax.persistence.UniqueConstraint Maven / Gradle / Ivy

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package javax.persistence;

import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

/**
 * Specifies that a unique constraint is to be included in the generated DDL for a primary or secondary table.
 * 
 *  *    Example:
 *    @Entity
 *    @Table(
 *        name="EMPLOYEE",
 *        uniqueConstraints=
 *            @UniqueConstraint(columnNames={"EMP_ID", "EMP_NAME"})
 *    )
 *    public class Employee { ... }
 * 
 * 
 * @since Java Persistence 1.0
 */
@Target({})
@Retention(RUNTIME)
public @interface UniqueConstraint {
	/**
	 * (Required) An array of the column names that make up the constraint.
	 */
	String[] columnNames();

	/**
	 * (Optional) Constraint name. A provider-chosen name will be chosen if a name is not specified.
	 * 
	 * @since Java Persistence 2.0
	 */
	String name() default "";
}