OnJava8-Examples/annotations/database/Constraints.java

// annotations/database/Constraints.java
// (c)2021 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
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package annotations.database;
import java.lang.annotation.*;

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Constraints {
  boolean primaryKey() default false;
  boolean allowNull() default true;
  boolean unique() default false;
}