android - SQLite 外键约束失败(代码 787)

Question

我在尝试升级数据库时遇到了 Foreign Key Constraint Failed (code 787) 错误。我所做的唯一更改是尝试向我的 InsertStatus 添加第 4 个条目。我环顾四周，我读到使用 ON DELETE CASCADE 应该可以解决我的问题，所以我尝试将它放在我所有的 FK 引用中并再次尝试，但仍然是同样的问题。

Logcat 指向我的 onUpgrade 和其中的所有 DROP TABLES(我尝试一次删除一个，看看哪些是坏的，显然它们都是).

我使用 ON DELETE CASCADE 错了吗？还是我的代码中有其他内容？

插入状态

void InsertStatus(SQLiteDatabase db) {
    ContentValues cv = new ContentValues();
    cv.put(colStatusID, 0);
    cv.put(colStatClass, "Active");
    db.insert(statTable, colStatusID, cv);
    cv.put(colStatusID, 1);
    cv.put(colStatClass, "Settled");
    db.insert(statTable, colStatusID, cv);
    cv.put(colStatusID, 2);
    cv.put(colStatClass, "Terminated");
    db.insert(statTable, colStatusID, cv);
    cv.put(colStatusID, 3);
    cv.put(colStatClass, "");
    db.insert(statTable, colStatusID, cv);
}

数据库助手

db.execSQL("CREATE TABLE " + termsTable + " (" + colTermsID + " INTEGER PRIMARY KEY , " + colTermsClass + " TEXT)");

    db.execSQL("CREATE TABLE " + periodTable + " (" + colPeriodID + " INTEGER PRIMARY KEY , " + colPeriodClass + " TEXT)");

    db.execSQL("CREATE TABLE " + statTable + " (" + colStatusID + " INTEGER PRIMARY KEY , " + colStatClass + " TEXT)");

    db.execSQL("CREATE TABLE " + accountsTable + " (" + colID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
            colName + " TEXT, " +
            colAmount + " Integer, " +
            colPurpose + " TEXT, " +
            colTerms + " INTEGER NOT NULL, " +
            colPeriod +" INTEGER NOT NULL, " +
            colBalance +" INTEGER, "+
            colStatus + " INTEGER DEFAULT '1'," +
            colDate + " TEXT, " +
            colEditDate + " TEXT, " +
            "FOREIGN KEY (" + colTerms + ") REFERENCES " + termsTable + " (" + colTermsID + ") ON DELETE CASCADE," +
            "FOREIGN KEY (" + colPeriod + ") REFERENCES " + periodTable + " (" + colPeriodID + ") ON DELETE CASCADE," +
            "FOREIGN KEY (" + colStatus + ") REFERENCES " + statTable + " (" + colStatusID + ") ON DELETE CASCADE);");

    db.execSQL("CREATE TABLE " + payTable + " (" + colPayID + " INTEGER PRIMARY KEY , " +
            colGroupID + " INTEGER NOT NULL, " +
            colPayBal + " TEXT, " +
            colInterest + " TEXT, " +
            colPayDue + " TEXT, " +
            colDateDue + " TEXT, " +
            colPaid + " Integer, " +
            "FOREIGN KEY (" + colGroupID + ") REFERENCES " + accountsTable + " (" + colID + ") ON DELETE CASCADE);");

    db.execSQL("CREATE VIEW " + viewAccs +
            " AS SELECT " + accountsTable + "." + colID + " AS _id," +
            " " + accountsTable + "." + colName + "," +
            " " + accountsTable + "." + colAmount + "," +
            " " + accountsTable + "." + colPurpose + "," +
            " " + termsTable + "." + colTermsClass + "," +
            " " + periodTable + "." + colPeriodClass + "," +
            " " + accountsTable+ "." + colBalance + "," +
            " " + statTable + "." + colStatClass + "," +
            " " + accountsTable + "." + colDate + "," +
            " " + accountsTable + "." + colEditDate + "" +
            " FROM " + accountsTable +
            " JOIN " + termsTable + " ON " + accountsTable + "." + colTerms + " = " + termsTable + "." + colTermsID +
            " JOIN " + periodTable + " ON " + accountsTable + "." + colPeriod + " = " + periodTable + "." + colPeriodID +
            " JOIN " + statTable + " ON " + accountsTable + "." + colStatus + " = " + statTable + "." + colStatusID );

    db.execSQL("CREATE VIEW " + viewPmnts +
            " AS SELECT " + payTable + "." + colPayID + " AS _id," +
            " " + accountsTable + "." + colID + "," +
            " " + payTable + "." + colGroupID + "," +
            " " + payTable + "." + colPayBal + "," +
            " " + payTable + "." + colInterest + "," +
            " " + payTable + "." + colPayDue + "," +
            " " + payTable + "." + colDateDue + "," +
            " " + payTable + "." + colPaid + "" +
            " FROM " + payTable +
            " JOIN " + accountsTable + " ON " + payTable + "." + colGroupID + " = " + accountsTable + "." + colID );

    InsertTerms(db);
    InsertPeriods(db);
    InsertStatus(db);
}

onUpgrade

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {


    db.execSQL("DROP TABLE IF EXISTS " + accountsTable);
    db.execSQL("DROP TABLE IF EXISTS " + termsTable);
    db.execSQL("DROP TABLE IF EXISTS " + periodTable);
    db.execSQL("DROP TABLE IF EXISTS " + statTable);
    db.execSQL("DROP TABLE IF EXISTS " + payTable);

    db.execSQL("DROP TRIGGER IF EXISTS acc_id_trigger");
    db.execSQL("DROP TRIGGER IF EXISTS acc_id_trigger22");
    db.execSQL("DROP TRIGGER IF EXISTS fk_accterm_termid");
    db.execSQL("DROP TRIGGER IF EXISTS fk_accperiod_periodid");
    db.execSQL("DROP TRIGGER IF EXISTS fk_accpay_payid");
    db.execSQL("DROP TRIGGER IF EXISTS fk_accstat_statid");

    db.execSQL("DROP VIEW IF EXISTS " + viewAccs);
    db.execSQL("DROP VIEW IF EXISTS " + viewPmnts);

    onCreate(db);
}

Answer 1

此处的错误与在其父实体存在之前创建子实体有关。

流程应该是:

1. 创建父级并获取父级 ID。
2. 创建子实体包含 引用 parent 身份

要添加更多详细信息，当您在 Room 实体上设置了 foreignKeys 数组值时，就会发生这种情况。因为您声明它将具有父列引用。如果这样做，请在尝试创建 child 之前确保您 parent 的引用有效。

因此，如果您在没有先拥有有效父 ID 的情况下创建子实体，您将抛出此 fatal error 。