SQLite支持外键
建议查看官网的说明书:
SQLite Foreign Key Support
描述外键
利用注解:ForeignKey来描述你的外键。
DBFlow根据你的描述信息,在建表的时候告诉sqlite去建立外键关联。
DBFlow生成 AModel_Table,其中的建表语句:
@Override
public final String getCreationQuery() {
return "CREATE TABLE IF NOT EXISTS `AModel`(`name` TEXT,`time` INTEGER,`otherModel` TEXT,`date` TEXT, PRIMARY KEY(`name`)"+ ", FOREIGN KEY(`otherModel`) REFERENCES " + FlowManager.getTableName(OtherModel.class) + "(`name`) ON UPDATE CASCADE ON DELETE CASCADE" + ");";
}
ok,任务完成!
ForeignKey的描述信息
package com.raizlabs.android.dbflow.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Description:
*/
@Retention(RetentionPolicy.SOURCE)
@Target(ElementType.FIELD)
public @interface ForeignKey {
/**
* Defines explicit references for a composite {@link ForeignKey} definition. This is no longer required
* as the library will auto-generate references for you based on the other table's primary keys.
*
* @return the set of explicit references if you wish to have different values than default generated.
*/
ForeignKeyReference[] references() default {};
/**
* @return Default false. When this column is a {@link ForeignKey} and table object,
* returning true will save the model before adding the fields to save as a foreign key.
* If false, we expect the field to not change and must save the model manually outside
* of the ModelAdapter before saving the child class.
*/
boolean saveForeignKeyModel() default false;
/**
* @return Default false. When this column is a {@link ForeignKey} and table object,
* returning true will delte the model before deleting its enclosing child class.
* If false, we expect the field to not change and must delete the model manually outside
* of the ModelAdapter before saving the child class.
*/
boolean deleteForeignKeyModel() default false;
/**
* @return Replaces legacy ForeignKeyContainer, this method instructs the code generator to only
* populate the model with the {@link ForeignKeyReference} defined in this field. This skips
* the Select retrieval convenience.
*/
boolean stubbedRelationship() default false;
/**
* @return an optional table class that this reference points to. It's only used if the field
* is NOT a Model class.
*/
Class<?> tableClass() default Object.class;
/**
* Defines {@link ForeignKeyAction} action to be performed
* on delete of referenced record. Defaults to {@link ForeignKeyAction#NO_ACTION}. Used only when
* columnType is {@link ForeignKey}.
*
* @return {@link ForeignKeyAction}
*/
ForeignKeyAction onDelete() default ForeignKeyAction.NO_ACTION;
/**
* Defines {@link ForeignKeyAction} action to be performed
* on update of referenced record. Defaults to {@link ForeignKeyAction#NO_ACTION}. Used only when
* columnType is {@link ForeignKey}.
*
* @return {@link ForeignKeyAction}
*/
ForeignKeyAction onUpdate() default ForeignKeyAction.NO_ACTION;
}
网友评论