我在数据库中创建第二个表时遇到问题。这是代码
public class CBDataBaseHelper {
public static final String KEY_ROWID = "_id";
public static final String KEY_NAME = "Recipe_Name";
public static final String KEY_CATEGORY = "Recipe_Category";
public static final String KEY_DESCRIPTION = "Recipe_Description";
public static final String KEY_ROWID2 = "_id";
public static final String fKEY_ROWID2 = "f_id";
public static final String KEY_NAME2 = "Ingredient_Name";
private static final String DATABASE_NAME = "Recipedb";
private static final String DATABASE_TABLE = "RecipeData";
private static final String DATABASE_TABLE2 = "IngredientData";
private static final int DATABASE_VERSION = 1;
private DBHelper myHelper;
private final Context mycontext;
private SQLiteDatabase mydatabase;
private static class DBHelper extends SQLiteOpenHelper {
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE " + DATABASE_TABLE + "( " + KEY_ROWID
+ " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_NAME
+ " TEXT NOT NULL, " + KEY_CATEGORY + " TEXT NOT NULL,"
+ KEY_DESCRIPTION + " TEXT NOT NULL" + ") ");
db.execSQL("CREATE TABLE " + DATABASE_TABLE2 + "( "
+ KEY_ROWID2 + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ KEY_NAME2 + " TEXT NOT NULL, "
+ fKEY_ROWID2 + " INTEGER , FOREIGN KEY " + "(" + fKEY_ROWID2 + ") " + "REFERENCES " + DATABASE_TABLE + " ( " + KEY_ROWID + " ))");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP IF EXISTS " + DATABASE_TABLE);
db.execSQL("DROP IF EXISTS " + DATABASE_TABLE2);
onCreate(db);
}
}
public CBDataBaseHelper(Context c){
mycontext = c;
}
public CBDataBaseHelper open() throws SQLException{
myHelper = new DBHelper(mycontext);
mydatabase = myHelper.getWritableDatabase();
return this;
}
public void close(){
myHelper.close();
}
public long createEntry(String name, String description, String category){
ContentValues cv = new ContentValues();
cv.put(KEY_NAME, name);
cv.put(KEY_CATEGORY, description);
cv.put(KEY_DESCRIPTION, category);
return mydatabase.insert(DATABASE_TABLE, null, cv);
}
public long createEntry2(String name){
ContentValues cv = new ContentValues();
cv.put(KEY_NAME2, name);
return mydatabase.insert(DATABASE_TABLE2, null, cv);
}
public Cursor query() {
// Open Database
String[] columns = new String[]{KEY_ROWID, KEY_NAME, KEY_CATEGORY, KEY_DESCRIPTION};
Cursor cursor = mydatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
return cursor;
}
public Cursor query2() {
// Open Database
String[] columns = new String[]{KEY_ROWID2, fKEY_ROWID2, KEY_NAME2};
Cursor cursor = mydatabase.query(DATABASE_TABLE2, columns, null, null, null, null, null);
return cursor;
}
public Cursor fetchRow(long rowId) throws SQLException {
Cursor mCursor = mydatabase.query(true, DATABASE_TABLE, new String[] { KEY_ROWID, KEY_NAME,
KEY_CATEGORY, KEY_DESCRIPTION }, KEY_ROWID + "="
+ rowId, null, null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
public boolean updateRecipe(long rowId, String RecipeName,
String RecipeCategory, String RecipeDescription)
{
ContentValues args = new ContentValues();
args.put(KEY_NAME, RecipeName);
args.put(KEY_DESCRIPTION, RecipeDescription);
args.put(KEY_CATEGORY, RecipeCategory);
return mydatabase.update(DATABASE_TABLE, args,
KEY_ROWID + "=" + rowId, null) > 0;
}
}
我有一个游标调用，然后访问了该数据库的第二个表，这是错误的出现，“没有这样的表”。有任何想法吗？
最佳答案
这是问题所在，尽管看起来有点傻。问题是您的创建数据库的onCreate没有被调用。我确定，但是您可以确认。同样，您的onUpgrade也没有被调用。原因是数据库已经存在，所以onCreate不会调用。现在您认为onUpgrade将被调用，但由于您未更改DATABASE_VERSION而不会被调用。
解析度：
通过命令实用程序“ adb shell”或使用文件浏览器通过eclipse删除数据库。该数据库位于“ / data / data // databases”下。
对于adb使用rm <db_name>
如果已经有一些数据（要保留以进行测试），则为其他解决方案，仅用于测试目的：
尝试将DATABASE_VERSION更改为当前值以外的其他值。这将导致您的onUpgrade被调用，因此编写您的sql，以免丢失数据。但是显然您的产量onUpgrade会与此不同。
关于android - SQLite不创建第二个表，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/8452113/