Question

因为FOREIGN KEY语法错误而没有创建我的表，但我似乎无法弄明白。在确定调用FK之前，我确保先创建了int。这是我的班级用FK的代码

public class PlayerStatsDatabase  {
public static final String KEY_ROWID = "_id";
public static final String PLAYER_ID = "PlayerId";
 public static final String KEY_SCORE = "Goals_Scored";
 public static final String KEY_MINUTES = "Minutes_Played";
 public static final String KEY_SUBIN = "Substitute_In";
 public static final String KEY_SUBOUT = "Substitute_Out";
 public static final String KEY_BOOKING = "Booked";

 private static final String TAG = "PlayersStatsDatabase";
 private DatabaseHelper mDbHelper;
 private SQLiteDatabase mDb;

 private static final String DATABASE_NAME = "Players";
 private static final String SQLITE_TABLE = "PlayerStats";
 private static final int DATABASE_VERSION = 2;

 private final Context mCtx;

 private static final String DATABASE_CREATE =
  "CREATE TABLE if not exists " + SQLITE_TABLE + " (" +
  KEY_ROWID + " integer PRIMARY KEY autoincrement," +
  PLAYER_ID + "integer"+" FOREIGN KEY ("+PLAYER_ID+") REFERENCES "+DATABASE_NAME+" ("+KEY_ROWID+"),"+
  KEY_SCORE + "," +
  KEY_MINUTES + "," +
  KEY_SUBIN + "," +
  KEY_SUBOUT + "," +
  KEY_BOOKING + ")" ;

主键位于此类

中

public class PlayerDbAdapter {

private static final String DATABASE_TABLE = "Players";
private static final String DATABASE_CREATE = "CREATE TABLE "+DATABASE_TABLE+" (_id integer primary key autoincrement, Player_Name text not null, Player_Position text not null, Player_Number text not null, Team text not null);";
private static final int DATABASE_VERSION =1;
  public static final String KEY_BODY = "Player_Name";
  public static final String KEY_ROWID = "_id";
  public static final String KEY_TITLE = "Player_Position";
  public static final String KEY_NUMBER = "Player_Number";
  public static final String KEY_TEAM = "Team";
private static final String TAG = "PlayerDbAdapter";
  private final Context mCtx;
  private SQLiteDatabase mDb;
  private DatabaseHelper mDbHelper;

  public PlayerDbAdapter(Context paramContext)
  {
    this.mCtx = paramContext;
  }

  public void close()
  {
    this.mDbHelper.close();
  }


  public long createPlayers(String playerName, String playerPosition, String playerNumber, String team)
  {
    ContentValues localContentValues = new ContentValues();
    localContentValues.put(KEY_BODY, playerName);
    localContentValues.put(KEY_TITLE, playerPosition);
    localContentValues.put(KEY_NUMBER, playerNumber);
    localContentValues.put(KEY_TEAM, team);
    try{
        return this.mDb.insert("Players", null, localContentValues);
    } catch (Exception e) {
        Log.e("Juma", e.getMessage());
    }

    return 0;
  }

logcat的

04-18 19:28:08.544: E/Database(352): Failure 1 (near "FOREIGN": syntax error) on 0x2b5840 when preparing 'CREATE TABLE if not exists PlayerStats (_id integer PRIMARY KEY autoincrement,PlayerIdinteger FOREIGN KEY (PlayerId) REFERENCES Players (_id),Goals_Scored,Minutes_Played,Substitute_In,Substitute_Out,Booked)'.

是因为我没有在oNCreate方法上插入Player_id吗？

Answer 1

这是我从SQLite documentation获取的一个修改示例：

CREATE TABLE track(
  KEY_ROWID   INTEGER PRIMARY KEY autoincrement, 
  PLAYER_ID   INTEGER, 
  KEY_SCORE   TEXT,
  FOREIGN KEY(PLAYER_ID) REFERENCES anotherTable(THE_KEY_ROWID_HERE),
  FOREIGN KEY(KEY_ROWID, PLAYER_ID) 
          REFERENCES yetAnotherTable(THE_KEY_ROWID_THERE, THE_PLAYER_ID_THERE)
);

如您所见，您必须在所有列定义之后添加外键 - 不要尝试将放在列定义中。您可以拥有多个，也可以使用组合列的外键。

最后在构建SQL String时要小心，你的语句是：

CREATE TABLE if not exists PlayerStats ( _id integer PRIMARY KEY autoincrement, PlayerId integer, Goals_Scored, Minutes_Played, ...

...缺少某些列的类型。

p.s。：这个应该可以使用，例如

private static final String TABLE_CREATE = "CREATE TABLE if not exists " + TABLE_NAME + " (" + KEY_ROWID + " integer PRIMARY KEY autoincrement," ANOTHER_COLUMN + " text" +")"; private static final String SQLITE_CREATE = "CREATE TABLE if not exists " + SQLITE_TABLE + " (" + KEY_ROWID + " integer PRIMARY KEY autoincrement," + PLAYER_ID + " integer," KEY_SCORE + " text," + KEY_MINUTES + " text," + KEY_SUBIN + " text," + KEY_SUBOUT + " text," + KEY_BOOKING + " text," +" FOREIGN KEY("+PLAYER_ID+") REFERENCES "+TABLE_NAME+" ("+KEY_ROWID+"))";

希望我能帮上忙。

干杯！

Answer 2

你必须在android sqlite中将主键的名称命名为_id。

Answer 3

根据日志，你在“FOREIGN”附近有一个语法错误，它清楚“除了整数之后的逗号”之外，“PlayerId”和“integer”之间没有空格。此外，你没有提交[Goals_Scored，Minutes_Played，Substitute_In，Substitute_Out，Booked]的类型。

我建议您了解有关SQL查询的更多信息，您可以从在桌面上使用sqlite开始。

未创建外键语法错误表

3 个答案: