0
我正在开发Android应用程序。它涉及SQLite数据库。我在一个数据库中创建了5个表并创建了5个DBAdapter。如何使用SQLite将数据库表和列连接在一起数据库
我有这些表（buddiesList，职称，事件，喜欢不喜欢&）键和外键的4个表（标题，事件，喜欢不喜欢&）的主键。这些表是在SQLite数据库中创建的。
哦，一个DBAdapter是我编码创建5个表并需要将这些表连接在一起的主键和&外键。而其他4个DBAdapter适用于5个表中的每一个。我只是发布代码，你可能会得到我说的和我需要的。
AnniversaryDBAdapter - 创建了5个表格。
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，该名_ID是链接到事件，爱憎表的主键。事件中的name_id，喜欢和不喜欢的表是从buddiesList表中检索的外键。但是，当我在“事件”页面中键入事件详细信息并将它们保存到事件表中时，表中的name_id应该是从buddiesList表中检索的数字，但是它会以名称而非ID的形式存储。喜欢和不喜欢也一样。
另外，如果取消对if(!db.isReadOnly()) { db.execSQL("PRAGMA foreign_keys = ON;"); }
我不能公开的信息，事件&短信页面，我得到了强制关闭的消息。
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的代码是类似于CalendarAdapter（事件表），LikesDBAdapter（喜欢表）& DislikesDBAdapter（不喜欢表）除外表的和列的名字
我的问题是，我不知道如何将表连接在一起。而且，如何在SQLite数据库中启用外键。
即使我键入比如
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;");
}
我仍然有部队密切错误。
另外，我不知道如何将buddiesList表中的name_id连接到事件，喜欢&不喜欢表。同样的做法是，将titles表中的title_id连接到事件表中的title_id。
任何人都可以帮我解决这个问题吗？任何帮助提供将不胜感激。
如果您显示错误的'logcat'输出将会很有帮助。 –