java - android.database.sqlite.SQLiteConstraintException : UNIQUE constraint failed:

Question

错误

 FATAL EXCEPTION: main
                                                                             Process: com.appmaster.akash.messageplus, PID: 14373
                                                                             android.database.sqlite.SQLiteConstraintException: UNIQUE constraint failed: UserData.RecieversID (code 1555)
                                                                                 at android.database.sqlite.SQLiteConnection.nativeExecuteForChangedRowCount(Native Method)
                                                                                 at android.database.sqlite.SQLiteConnection.executeForChangedRowCount(SQLiteConnection.java:734)
                                                                                 at android.database.sqlite.SQLiteSession.executeForChangedRowCount(SQLiteSession.java:754)
                                                                                 at android.database.sqlite.SQLiteStatement.executeUpdateDelete(SQLiteStatement.java:64)
                                                                                 at android.database.sqlite.SQLiteDatabase.updateWithOnConflict(SQLiteDatabase.java:1579)
                                                                                 at android.database.sqlite.SQLiteDatabase.update(SQLiteDatabase.java:1525)
                                                                                 at com.appmaster.akash.messageplus.Chat.mMessagesSent(Chat.java:918)
                                                                                 at com.appmaster.akash.messageplus.Chat.sendMessage(Chat.java:709)
                                                                                 at com.appmaster.akash.messageplus.Chat.access$900(Chat.java:76)
                                                                                 at com.appmaster.akash.messageplus.Chat$5.onClick(Chat.java:442)
                                                                                 at android.view.View.performClick(View.java:6256)
                                                                                 at android.view.View$PerformClick.run(View.java:24701)
                                                                                 at android.os.Handler.handleCallback(Handler.java:789)
                                                                                 at android.os.Handler.dispatchMessage(Handler.java:98)
                                                                                 at android.os.Looper.loop(Looper.java:164)
                                                                                 at android.app.ActivityThread.main(ActivityThread.java:6541)
                                                                                 at java.lang.reflect.Method.invoke(Native Method)
                                                                                 at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
                                                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

插入

 MainData helper = new MainData(this); //Change the name to your Helper Class name
    SQLiteDatabase db = helper.getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put(KEY_ID, MessageRecieverId);
    contentValues.put(KEY_NAME, MessageRecieverName);
    contentValues.put(KEY_MESSAGES_SENT, 0);
    contentValues.put(KEY_MESSAGES_RECIEVED, 0);
    contentValues.put(KEY_TIME_SPENT, "");

    long returnVariable = db.insert(TABLE_USER_DATA,null,contentValues);
    if (returnVariable == -1) {
        Toast.makeText(getApplication(), "Nope", Toast.LENGTH_LONG).show();

插入没有问题，但更新时出现此错误

正在更新

 MainData helper = new MainData(this); //Change the name to your Helper Class name
    SQLiteDatabase db = helper.getWritableDatabase();int userData = 0;
    Cursor data2 = helper.getUserData();
    while (data2.moveToNext()) {
        userData = data2.getInt(data2.getColumnIndex("MessagesSent"));
    }
    ContentValues contentValues2 = new ContentValues();
    contentValues2.put(KEY_ID, MessageRecieverId);
    contentValues2.put(KEY_MESSAGES_SENT, userData+1);
    long returnVariable2 = db.update(TABLE_USER_DATA, contentValues2,null,null);
    if (returnVariable2 == -1) {
        Toast.makeText(getApplication(), "Nope", Toast.LENGTH_LONG).show();
        //-1 means there was an error updating the values
    } else {
        Toast.makeText(getApplication(),"uf", Toast.LENGTH_SHORT).show();
    }

谁知道为什么会这样？ ..................................................... ..................................................... ...........................................................

Answer 1

您可能使用 id 列 (KEY_ID) 的值进行插入。此列上的赔率定义为 INTEGER PRIMARY KEY 或 INTEGER PRIMARY KEY AUTOINCREMENT。

通常您不会为此类列指定值，因为 SQLite 会分配一个唯一值(通常比分配的最高值大 1)。

如果您为这样的列指定一个值，并且表中的一行已经在该列中具有该值，则将违反 PRIMARY KEY 隐含的 UNIQUE 约束因为这违反了 PRIMARY KEY 必须是唯一 的规则。

我建议您使用:-

MainData helper = new MainData(this); //Change the name to your Helper Class name
SQLiteDatabase db = helper.getWritableDatabase();
ContentValues contentValues = new ContentValues();
//contentValues.put(KEY_ID, MessageRecieverId); //<<<<<<<<<< COMMENTED OUT (can delete the line)
contentValues.put(KEY_NAME, MessageRecieverName);
contentValues.put(KEY_MESSAGES_SENT, 0);
contentValues.put(KEY_MESSAGES_RECIEVED, 0);
contentValues.put(KEY_TIME_SPENT, "");

long returnVariable = db.insert(TABLE_USER_DATA,null,contentValues);
if (returnVariable == -1) {
    Toast.makeText(getApplication(), "Nope", Toast.LENGTH_LONG).show();

returnVariable 将成为插入行时分配的 id 列 (KEY_ID) 的值。

• 注意 id 列并不一定意味着该列被命名为 id，而是由于它的定义方式，它是一个特殊的列。也就是说，通过指定 INTEGER PRIMARY KEY，该列实际上是通常隐藏的 rowid 列的别名(除非 TABLE 是用 WITHOUT ROWID 短语定义的)。

您可能会发现阅读 SQLite Autoincrement有帮助。