TableColumn.java

package com.base.db;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

/**
 * Annotation used for describing table's columns. If you use this notion
 * for a static field from class, it will visible as a table column. The
 * type of the column is mandatory. Additionally you can mark a field as a
 * primary key, index it, add "not null"/"unique" property.
 */
@Retention(RetentionPolicy.RUNTIME)
public @interface TableColumn {
    public enum Types {
        INTEGER, TEXT, BLOB, DATETIME
    }

    Types type() default Types.TEXT;

    boolean isPrimary() default false;

    boolean isIndex() default false;

    /**
     * A NOT NULL constraint may only be attached to a column definition,
     * not specified as a table constraint. Not surprisingly, a NOT NULL
     * constraint dictates that the associated column may not contain a NULL
     * value. Attempting to set the column value to NULL when inserting a
     * new row or updating an existing one causes a constraint violation.
     */

    boolean isNotNull() default false;

    /**
     * A UNIQUE constraint is similar to a PRIMARY KEY constraint, except
     * that a single table may have any number of UNIQUE constraints. For
     * each UNIQUE constraint on the table, each row, isPrimary=true must
     * feature a unique combination of values in the columns identified by
     * the UNIQUE constraint. As with PRIMARY KEY constraints, for the
     * purposes of UNIQUE constraints NULL values are considered distinct
     * from all other values (including other NULLs). If an INSERT or UPDATE
     * statement attempts to modify the table content so that two or more
     * rows feature identical values in a set of columns that are subject to
     * a UNIQUE constraint, it is a constraint violation.
     */
    boolean isUnique() default false;
    
}