android - SQLite 自动增量不起作用

Question

好的，这不是垃圾邮件，应该很简单我不知道为什么它不起作用这是我的代码：

gamesdatabase = openOrCreateDatabase("GamesDatabase", MODE_PRIVATE, null);
gamesdatabase.execSQL("CREATE TABLE IF NOT EXISTS Games (ID INTEGER PRIMARY KEY, Name
VARACHAR, NPlayers INT(1), NRounds INT(2), WinScore INT(2));");

gamesdatabase.execSQL("INSERT INTO Games 
(ID, Name, NPlayers, NRounds, WinScore ) VALUES ( NULL, 'TAWLA',2,0,0 );");

gamesdatabase.execSQL("INSERT INTO Games 
(ID, Name, NPlayers, NRounds, WinScore ) VALUES ( NULL, 'DOMANA',4,0,0 );");


Cursor c = gamesdatabase.rawQuery("SELECT * FROM Games", null);
c.moveToFirst();
while (c.isAfterLast() == false) {
Log.d("BEZRA", String.valueOf(c.getInt(c.getColumnIndex("ID"))));
c.moveToNext();
}

这有什么问题？日志显示所有记录为 0

Answer 1

SQLite 表的主键称为 _id。它是自动递增的，您不应该尝试将值插入其中。

gamesdatabase = openOrCreateDatabase("GamesDatabase", MODE_PRIVATE, null);
gamesdatabase.execSQL("CREATE TABLE IF NOT EXISTS Games (_id INTEGER PRIMARY KEY, Name
VARACHAR, NPlayers INT(1), NRounds INT(2), WinScore INT(2));");

gamesdatabase.execSQL("INSERT INTO Games 
(Name, NPlayers, NRounds, WinScore ) VALUES ('TAWLA',2,0,0 );");

gamesdatabase.execSQL("INSERT INTO Games 
(Name, NPlayers, NRounds, WinScore ) VALUES ('DOMANA',4,0,0 );");


Cursor c = gamesdatabase.rawQuery("SELECT * FROM Games", null);
c.moveToFirst();
while (c.isAfterLast() == false) {
Log.d("BEZRA", String.valueOf(c.getInt(c.getColumnIndex("_id"))));
c.moveToNext();
}

Answer 2

对我有用的是将我的创建类型从 INT 重命名为 INTEGER 并开始工作。

由此：

CREATE TABLE IF NOT EXISTS foo (id INT PRIMARY KEY, bar INT)

对此：

CREATE TABLE IF NOT EXISTS foo (id INTEGER PRIMARY KEY, bar INT)

Answer 3

c.getColumnIndex("ID") 获取列的索引，其中 ID 为 0 索引列，名称为 1 等

你要

c.getInt(c.getColumnIndex("ID"))

Answer 4

您可以看到 http://alvinalexander.com/android/sqlite-autoincrement-serial-identity-primary-key 示例 CRETAE_TABLE

  CREATE TABLE salespeople (
  id INTEGER PRIMARY KEY,
  first_name TEXT NOT NULL,
  last_name TEXT NOT NULL,
  commission_rate REAL NOT NULL
);

插入数据

 INSERT INTO salespeople VALUES (null, 'Fred', 'Flinstone', 10.0);

- -或者 - -

INSERT INTO salespeople (first_name, last_name, commission_rate) VALUES ('Fred', 'Flinstone', 10.0);

Answer 5

您想告诉它该列是自动递增的。

ID INTEGER PRIMARY KEY AUTO_INCREMENT NOT NULL

反而。

Answer 6

因为您没有将其设置为自动递增。主键是不够的。

CREATE TABLE IF NOT EXISTS Games (ID INTEGER PRIMARY KEY AUTOINCREMENT, Name VARACHAR, NPlayers INT(1), NRounds INT(2), WinScore INT(2));