我收到此错误
07-16 20:58:27.299: E/AndroidRuntime(14005): Caused by: android.database.sqlite.SQLiteException: no such table: strings: , while compiling: SELECT id, string FROM strings WHERE id = ?
我有 StringDB 类,它具有 ID 和 String 来将此类的对象存储到 SQLite 数据库中。请调试并给出解决方案。这是代码:
public class MySQLiteHelper extends SQLiteOpenHelper {
// Database Version
private static final int DATABASE_VERSION = 2;
// Database Name
private static final String DATABASE_NAME = "StringDB";
public MySQLiteHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
// SQL statement to create StringDB table
String CREATE_StringDB_TABLE = "CREATE TABLE StringDBs ( " +
"id INTEGER PRIMARY KEY AUTOINCREMENT, " +"string"+ "TEXT )";
// create StringDBs table
db.execSQL(CREATE_StringDB_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older StringDBs table if existed
db.execSQL("DROP TABLE IF EXISTS StringDBs");
// create fresh StringDBs table
this.onCreate(db);
}
//---------------------------------------------------------------------
/**
* CRUD operations (create "add", read "get", update, delete) StringDB + get all StringDBs + delete all StringDBs
*/
// StringDBs table name
private static final String TABLE_STRINGS = "strings";
// StringDBs Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_STRING= "string";
private static final String[] COLUMNS = {KEY_ID,KEY_STRING};
public void addStringDB(StringDB string){
// 1. get reference to writable DB
SQLiteDatabase db = this.getWritableDatabase();
// 2. create ContentValues to add key "column"/value
ContentValues values = new ContentValues();
values.put(KEY_STRING, string.getString()); // get author
// 3. insert
db.insert(TABLE_STRINGS, // table
null, //nullColumnHack
values); // key/value -> keys = column names/ values = column values
// 4. close
db.close();
}
public StringDB getStringDB(int id){
// 1. get reference to readable DB
SQLiteDatabase db = this.getReadableDatabase();
// 2. build query
Cursor cursor =
db.query(TABLE_STRINGS, // a. table
COLUMNS, // b. column names
" id = ?", // c. selections
new String[] { String.valueOf(id) }, // d. selections args
null, // e. group by
null, // f. having
null, // g. order by
null); // h. limit
// 3. if we got results get the first one
if (cursor != null)
cursor.moveToFirst();
// 4. build StringDB object
StringDB res=new StringDB();
res.setId(Integer.parseInt(cursor.getString(0)));
res.setString(cursor.getString(1));
return res;
}
// Get All StringDBs
public List<StringDB> getAllStringDBs() {
List<StringDB> StringDBs = new LinkedList<StringDB>();
// 1. build the query
String query = "SELECT * FROM " + TABLE_STRINGS;
// 2. get reference to writable DB
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(query, null);
// 3. go over each row, build StringDB and add it to list
StringDB StringDB = null;
if (cursor.moveToFirst()) {
do {
StringDB = new StringDB();
StringDB.setId(Integer.parseInt(cursor.getString(0)));
StringDB.setString(cursor.getString(1));
// Add StringDB to StringDBs
StringDBs.add(StringDB);
} while (cursor.moveToNext());
}
Log.d("getAllStringDBs()", StringDBs.toString());
// return StringDBs
return StringDBs;
}
// Updating single StringDB
public int updateStringDB(StringDB StringDB) {
// 1. get reference to writable DB
SQLiteDatabase db = this.getWritableDatabase();
// 2. create ContentValues to add key "column"/value
ContentValues values = new ContentValues();
values.put("strings", StringDB.getString()); // get author
// 3. updating row
int i = db.update(TABLE_STRINGS, //table
values, // column/value
KEY_ID+" = ?", // selections
new String[] { String.valueOf(StringDB.getId()) }); //selection args
// 4. close
db.close();
return i;
}
// Deleting single StringDB
public void deleteStringDB(StringDB StringDB) {
// 1. get reference to writable DB
SQLiteDatabase db = this.getWritableDatabase();
// 2. delete
db.delete(TABLE_STRINGS,
KEY_ID+" = ?",
new String[] { String.valueOf(StringDB.getId()) });
// 3. close
db.close();
Log.d("deleteStringDB", StringDB.toString());
}
}