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我正在開發Android應用程序。它涉及SQLite數據庫。我在一個數據庫中創建了5個表並創建了5個DBAdapter。如何使用SQLite將數據庫表和列連接在一起數據庫
我有這些表（buddiesList，職稱，事件，喜歡不喜歡&）鍵和外鍵的4個表（標題，事件，喜歡不喜歡&）的主鍵。這些表是在SQLite數據庫中創建的。
哦，一個DBAdapter是我編碼創建5個表並需要將這些表連接在一起的主鍵和&外鍵。而其他4個DBAdapter適用於5個表中的每一個。我只是發佈代碼，你可能會得到我說的和我需要的。
AnniversaryDBAdapter - 創建了5個表格。
public class AnniversaryDBAdapter
{
private static final String DATABASE_NAME = "Tables";
private static final int DATABASE_VERSION = 2;
private static final String CREATE_TABLE_TITLE = "create table titles(title_id integer primary key autoincrement, title text not null, image text not null);";
private static final String CREATE_TABLE_BUDDIESLIST = "create table buddiesList(name_id integer primary key autoincrement, name text not null);";
private static final String CREATE_TABLE_LIKES = "create table likes(likes_id integer primary key autoincrement,like text not null, name_id integer not null, FOREIGN KEY(name_id) REFERENCES buddiesList(name_id));";
private static final String CREATE_TABLE_DISLIKES = "create table dislikes(dlike_id integer primary key autoincrement, dislike text not null, name_id integer not null, FOREIGN KEY(name_id) REFERENCES buddiesList(name_id));";
private static final String CREATE_TABLE_EVENTS = "create table event(event_id integer primary key autoincrement, title_id integer not null, location text not null, starttime text not null, endtime text not null, desc text not null, date text not null, name_id integer not null, FOREIGN KEY(title_id) REFERENCES titles(title_id));";
private final Context context;
private static final String TAG = "DBAdapter";
private DatabaseHelper DBHelper;
protected SQLiteDatabase db;
private static String DB_PATH = "/data/data/main.page/Tables/";
public AnniversaryDBAdapter(Context aContext)
{
this.context = aContext;
DBHelper = new DatabaseHelper(context);
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
/*try
{
database.execSQL(CREATE_TABLE_BUDDIESLIST);
database.execSQL(CREATE_TABLE_LIKES);
database.execSQL(CREATE_TABLE_EVENTS);
database.execSQL(CREATE_TABLE_TITLE);
database.execSQL(CREATE_TABLE_DISLIKES);
}catch(SQLException e)
{
e.printStackTrace();
}*/
db.execSQL(CREATE_TABLE_BUDDIESLIST);
db.execSQL(CREATE_TABLE_LIKES);
db.execSQL(CREATE_TABLE_EVENTS);
db.execSQL(CREATE_TABLE_TITLE);
db.execSQL(CREATE_TABLE_DISLIKES);
/* database.execSQL("CREATE TRIGGER fk_budevent_nameid" +
"BEFORE INSERT" +
"ON events FOR EACH ROW BEGIN" +
"SELECT CASE WHEN((SELECT name_id FROM buddiesList WHERE name_id = new.name_id) IS NULL)" +
"THEN RAISE(ABORT, 'Foreign Key Violation')END;" +
"END;");
*/
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
Log.w(TAG, "Upgrading database from version "+oldVersion+" to "+newVersion+", which will destroy all old data");
onCreate(db);
}
}
public AnniversaryDBAdapter open() throws SQLException
{
db = this.DBHelper.getWritableDatabase();
/* if(!db.isReadOnly())
{
db.execSQL("PRAGMA foreign_keys = ON;");
}*/
return this;
}
public void close()
{
DBHelper.close();
}
/*
public long insertEvent(String title,String location,String starttime,String endtime,String desc,String date, String name)
{
ContentValues cValues = new ContentValues();
cValues.put(KEY_TITLE, title);
cValues.put(KEY_LOCATION, location);
cValues.put(KEY_START, starttime);
cValues.put(KEY_END, endtime);
cValues.put(KEY_DESC, desc);
cValues.put(KEY_ALARM, alarm);
cValues.put(KEY_DATE, date);
cValues.put(KEY_NAME, name);
return db.insert(CREATE_TABLE_EVENTS, null, cValues);
}
public boolean deleteEvent(long rowId)
{
return db.delete(CREATE_TABLE_EVENTS, KEY_ROWID + "=" + rowId, null) > 0;
}
public Cursor getAllEvents()
{
return db.query(CREATE_TABLE_EVENTS, new String[] {KEY_ROWID, KEY_TITLE, KEY_LOCATION, KEY_START, KEY_END, KEY_DESC, KEY_DATE, KEY_NAME}, null, null, null, null, null);
}
public Cursor getEvent(long rowId) throws SQLException
{
Cursor c = db.query(true,CREATE_TABLE_EVENTS, new String[] {KEY_ROWID, KEY_TITLE, KEY_LOCATION, KEY_START, KEY_END, KEY_DESC, KEY_DATE, KEY_NAME}, KEY_ROWID + "=" + rowId, null, null, null, null, null);
if(c != null)
{
c.moveToFirst();
}
return c;
}
*/
}
正如你可以看到AnniversaryDBAdapter在buddiesList表，該名_ID是鏈接到事件，愛憎表的主鍵。事件中的name_id，喜歡和不喜歡的表是從buddiesList表中檢索的外鍵。但是，當我在「事件」頁面中鍵入事件詳細信息並將它們保存到事件表中時，表中的name_id應該是從buddiesList表中檢索的數字，但是它會以名稱而非ID的形式存儲。喜歡和不喜歡也一樣。
另外，如果取消對if(!db.isReadOnly()) { db.execSQL("PRAGMA foreign_keys = ON;"); }
我不能公開的信息，事件&短信頁面，我得到了強制關閉的消息。
BuddyDBAdapter - buddiesList表
public class BuddyDBAdapter extends AnniversaryDBAdapter
{
public static final String KEY_ROWID = "name_id";
public static final String KEY_NAME = "name";
private static final String TAG = "DBAdapter";
private static final String CREATE_TABLE_BUDDIESLIST = "buddiesList";
//private SQLiteDatabase db;
public BuddyDBAdapter(Context aContext)
{
super(aContext);
}
public long insertNames(String name)
{
ContentValues buddyValues = new ContentValues();
buddyValues.put(KEY_NAME, name);
return db.insert(CREATE_TABLE_BUDDIESLIST, null, buddyValues);
}
public boolean deleteNames(long rowId)
{
return db.delete(CREATE_TABLE_BUDDIESLIST, KEY_ROWID + "=" + rowId, null) > 0;
}
public Cursor getAllNames()
{
return db.query(CREATE_TABLE_BUDDIESLIST, new String[] { KEY_ROWID, KEY_NAME }, null, null, null, null, null);
}
public Cursor getNames(long rowId) throws SQLException
{
Cursor c = db.query(true, CREATE_TABLE_BUDDIESLIST, new String[] { KEY_ROWID, KEY_NAME }, KEY_ROWID + "=" + rowId, null, null, null, null, null);
if(c != null)
{
c.moveToFirst();
}
return c;
}
}
在BuddyDBAdapter的代碼是類似於CalendarAdapter（事件表），LikesDBAdapter（喜歡錶）& DislikesDBAdapter（不喜歡錶）除外表的和列的名字
我的問題是，我不知道如何將表連接在一起。而且，如何在SQLite數據庫中啓用外鍵。
即使我鍵入比如
private static final String CREATE_TABLE_TITLE = "create table titles(title_id integer primary key autoincrement, title text not null, image text not null);";
private static final String CREATE_TABLE_BUDDIESLIST = "create table buddiesList(name_id integer primary key autoincrement, name text not null);";
private static final String CREATE_TABLE_LIKES = "create table likes(likes_id integer primary key autoincrement,like text not null, name_id integer not null, FOREIGN KEY(name_id) REFERENCES buddiesList(name_id));";
private static final String CREATE_TABLE_DISLIKES = "create table dislikes(dlike_id integer primary key autoincrement, dislike text not null, name_id integer not null FOREIGN KEY(name_id) REFERENCES buddiesList(name_id));";
private static final String CREATE_TABLE_EVENTS = "create table event(event_id integer primary key autoincrement, title_id integer not null, location text not null, starttime text not null, endtime text not null, desc text not null, date text not null, name_id integer not null, FOREIGN KEY(name_id) REFERENCES buddiesList(name_id), FOREIGN KEY(title_id) REFERENCES titles(title_id));";
和
if(!db.isReadOnly())
{
db.execSQL("PRAGMA foreign_keys = ON;");
}
我仍然有部隊密切錯誤。
另外，我不知道如何將buddiesList表中的name_id連接到事件，喜歡&不喜歡錶。同樣的做法是，將titles表中的title_id連接到事件表中的title_id。
任何人都可以幫我解決這個問題嗎？任何幫助提供將不勝感激。
如果您顯示錯誤的'logcat'輸出將會很有幫助。 –