Java sqlite数据库未填充,查询';s不';行不通
我无法处理申请中的问题。有两个类用于处理数据库,但它们只是创建db并在其中创建一个表,但基没有填充,并且在出现严重错误时查询数据库,这表明数据库为空。请帮帮我 一级数据库:Java sqlite数据库未填充,查询';s不';行不通,java,android,sql,database,sqlite,Java,Android,Sql,Database,Sqlite,我无法处理申请中的问题。有两个类用于处理数据库,但它们只是创建db并在其中创建一个表,但基没有填充,并且在出现严重错误时查询数据库,这表明数据库为空。请帮帮我 一级数据库: package ru.psdevteam.syndicttest.app; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelp
package ru.psdevteam.syndicttest.app;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class SynDB extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "synonyms.db";
public static final String TABLE_NAME = "words";
private static final int DATABASE_VERSION = 1;
public static final String WordID = "_id";
public static final String Word = "word";
private static final String SQL_CREATE_ENTRIES = "CREATE TABLE "
+ TABLE_NAME + " (" + WordID + " INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL ,"
+ Word + " text NOT NULL); ";
public static final String SQL_INSERT_WORDS = "INSERT INTO " + TABLE_NAME + " (_id,word) " + "VALUES " + "(1,'а'),(2,'же'),(3,'да'),(4,'напротив'),(5,'но'),(6,'ан'),(7,'однако'),(8,'инак'),(9,'следовательно'),(10,'потом')";
private static final String SQL_DELETE_ENTRIES = "DROP TABLE IF EXISTS "
+ TABLE_NAME;
public SynDB(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(SQL_CREATE_ENTRIES);
db.execSQL(SQL_INSERT_WORDS);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w("LOG_TAG", "Обновление базы данных с версии " + oldVersion
+ " до версии " + newVersion + ", которое удалит все старые данные");
db.execSQL(SQL_DELETE_ENTRIES);
onCreate(db);
}
}
package ru.psdevteam.syndicttest.app;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class IdDB extends SQLiteOpenHelper {
//constants
private static final String DATABASE_NAME = "synonyms.db";
public static final String TABLE_NAME_2 = "synonyms";
private static final int DATABASE_VERSION = 1;
public static final String StringID = "s_id";
public static final String SynWordID = "w_id";
// test database with test data inside
private static final String SQL_CREATE_ENTRIES = "CREATE TABLE "
+ TABLE_NAME_2 + " (" + SynWordID + " INTEGER NOT NULL ,"
+ StringID + " INTEGER NOT NULL); ";
public static final String SQL_INSERT_IDS = "INSERT INTO " + TABLE_NAME_2 + " (w_id,s_id) " + "VALUES " + "(1,2),(1,3),(1,4),(1,5),(1,6),(1,7),(1,8),(1,9),(1,10)";
private static final String SQL_DELETE_ENTRIES = "DROP TABLE IF EXISTS " + TABLE_NAME_2;
public IdDB(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase dbsyn) {
dbsyn.execSQL(SQL_CREATE_ENTRIES);
dbsyn.execSQL(SQL_INSERT_IDS);
}
@Override
public void onUpgrade(SQLiteDatabase dbsyn, int oldSynVersion, int newSynVersion) {
Log.w("LOG_TAG", "Обновление базы данных с версии " + oldSynVersion
+ " до версии " + newSynVersion + ", которое удалит все старые данные");
dbsyn.execSQL(SQL_DELETE_ENTRIES);
onCreate(dbsyn);
}
}
第二个DB类:
package ru.psdevteam.syndicttest.app;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class SynDB extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "synonyms.db";
public static final String TABLE_NAME = "words";
private static final int DATABASE_VERSION = 1;
public static final String WordID = "_id";
public static final String Word = "word";
private static final String SQL_CREATE_ENTRIES = "CREATE TABLE "
+ TABLE_NAME + " (" + WordID + " INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL ,"
+ Word + " text NOT NULL); ";
public static final String SQL_INSERT_WORDS = "INSERT INTO " + TABLE_NAME + " (_id,word) " + "VALUES " + "(1,'а'),(2,'же'),(3,'да'),(4,'напротив'),(5,'но'),(6,'ан'),(7,'однако'),(8,'инак'),(9,'следовательно'),(10,'потом')";
private static final String SQL_DELETE_ENTRIES = "DROP TABLE IF EXISTS "
+ TABLE_NAME;
public SynDB(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(SQL_CREATE_ENTRIES);
db.execSQL(SQL_INSERT_WORDS);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w("LOG_TAG", "Обновление базы данных с версии " + oldVersion
+ " до версии " + newVersion + ", которое удалит все старые данные");
db.execSQL(SQL_DELETE_ENTRIES);
onCreate(db);
}
}
package ru.psdevteam.syndicttest.app;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class IdDB extends SQLiteOpenHelper {
//constants
private static final String DATABASE_NAME = "synonyms.db";
public static final String TABLE_NAME_2 = "synonyms";
private static final int DATABASE_VERSION = 1;
public static final String StringID = "s_id";
public static final String SynWordID = "w_id";
// test database with test data inside
private static final String SQL_CREATE_ENTRIES = "CREATE TABLE "
+ TABLE_NAME_2 + " (" + SynWordID + " INTEGER NOT NULL ,"
+ StringID + " INTEGER NOT NULL); ";
public static final String SQL_INSERT_IDS = "INSERT INTO " + TABLE_NAME_2 + " (w_id,s_id) " + "VALUES " + "(1,2),(1,3),(1,4),(1,5),(1,6),(1,7),(1,8),(1,9),(1,10)";
private static final String SQL_DELETE_ENTRIES = "DROP TABLE IF EXISTS " + TABLE_NAME_2;
public IdDB(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase dbsyn) {
dbsyn.execSQL(SQL_CREATE_ENTRIES);
dbsyn.execSQL(SQL_INSERT_IDS);
}
@Override
public void onUpgrade(SQLiteDatabase dbsyn, int oldSynVersion, int newSynVersion) {
Log.w("LOG_TAG", "Обновление базы данных с версии " + oldSynVersion
+ " до версии " + newSynVersion + ", которое удалит все старые данные");
dbsyn.execSQL(SQL_DELETE_ENTRIES);
onCreate(dbsyn);
}
}
和主要活动:
package ru.psdevteam.syndicttest.app;
import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
public class MainActivity extends Activity implements OnClickListener {
final String LOG_TAG = "myLogs";
IdDB idh;
SynDB sqh;
SQLiteDatabase sqdb, iddb;
Button btnOk;
EditText etWord;
String eWord;
String[] syns = { "Synonym1", "Synonym2", "Synonym3", "Synonym4", "Synonym5", "Synonym6", // it's just for example. I must change it for display list of synonyms from DB
"Synonym7", "Synonym8", "Synonym9", "Synonym10", "Synonym11" };
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
etWord = (EditText) findViewById(R.id.etWord);
btnOk = (Button) this.findViewById(R.id.btnOk);
ListView lvMain = (ListView) findViewById(R.id.lvMain);
btnOk.setOnClickListener(btnOkListener);
//initialize our class-cover IdDB
idh = new IdDB(this);
// initialize our class-cover SynDB
sqh = new SynDB(this);
// we need db to read and write
sqdb = sqh.getWritableDatabase();
iddb = idh.getWritableDatabase();
// создаем адаптер
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, syns);
// присваиваем адаптер списку
lvMain.setAdapter(adapter);
}
public OnClickListener btnOkListener = new OnClickListener(){
@Override
public void onClick(View v) {
eWord = etWord.getText().toString();
switch (v.getId()){
//if "Ок" is pressed (it is the only one)
case R.id.btnOk:
//i want to unite all my queries and out in listView result of FinalQuery
String query = "SELECT " + SynDB.WordID +" FROM " + SynDB.TABLE_NAME + " WHERE " + SynDB.Word + " ='" + eWord + "'"; // first query: here you enter the word and search it's ID in the table
String IdQuery = "SELECT " + IdDB.SynWordID +"," + IdDB.StringID + " FROM " + IdDB.TABLE_NAME_2 + " WHERE " + IdDB.SynWordID + " ='" + 1 + "' " + "or " + IdDB.StringID + " ='" + 1 + "'";// second query: here ID from first table compare with ID from second table
String FinalQuery = "SELECT " + SynDB.Word + " FROM " + SynDB.TABLE_NAME + " WHERE " + SynDB.WordID + " IN " + "('1','2','3','4')" ; // wrong final query. here should be selected already sorted by ID synonyms
Cursor cursor3 = iddb.rawQuery(IdQuery, null);
Cursor cursorLast = sqdb.rawQuery(FinalQuery, null);
Log.d(LOG_TAG, "--- Rows in mytable: ---");
// делаем запрос всех данных из таблицы words, получаем Cursor
Cursor cursor2 = sqdb.rawQuery(query, null);
// ставим позицию курсора на первую строку выборки
// если в выборке нет строк, вернется false
if (cursor2.moveToFirst()) {
// определяем номера столбцов по имени в выборке
int idColIndex = cursor2.getColumnIndex("_id");
int wordColIndex = cursor2.getColumnIndex("word");
do {
// получаем значения по номерам столбцов и пишем все в лог
Log.d(LOG_TAG,
"_id = " + cursor2.getInt(idColIndex) +
", word = " + cursor2.getString(wordColIndex));
// переход на следующую строку
// а если следующей нет (текущая - последняя), то false - выходим из цикла
} while (cursor2.moveToNext());
} else
Log.d(LOG_TAG, "0 rows");
cursor2.close();
break;
default:
break;
} // close switch
} // close onClick
};
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
// закрываем соединения с базой данных
sqdb.close();
sqh.close();
}
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onClick(View view) {
}
}
\u id
字段是自动增量
不要在查询中提供它。像
public static final String SQL_INSERT_WORDS = "INSERT INTO " + TABLE_NAME + " (word) " + "VALUES " + "('а'),('же'),('да'),('напротив')...
你的问题是
String query = "SELECT " + SynDB.WordID +" FROM " + SynDB.TABLE_NAME + " WHERE " + SynDB.Word + " ='" + eWord + "'"; // first query: here you enter the word and search it's ID in the table
只选择一列
然后尝试在那里获取两列:
int idColIndex = cursor2.getColumnIndex("_id");
int wordColIndex = cursor2.getColumnIndex("word");
// ...
Log.d(LOG_TAG,
"_id = " + cursor2.getInt(idColIndex) +
", word = " + cursor2.getString(wordColIndex));
getColumnIndex()
对于光标中不存在的列返回-1
将
单词添加到选择以将其包含在光标中。多么严重的错误?如果出现异常,张贴StackTrace我没有看到您在哪里填写数据库。只能对ListView适配器使用syns数组。Ofc db为空。在SynDB类中有行“db.execSQL(SQL_INSERT_WORDS);”。它必须用数据填充我的表也许我应该删除自动增值值?数据库中已经存在大约200000个单词,这是可能的解决方案。如果删除它,则必须为每个记录提供唯一的id。谢谢!请告诉我如何修复我的最后一个请求,特别是“IN”()的一部分。括号中应该是选择题,但我不太明白如何做ID的多选题,我不明白最后一个问题。这个查询看起来不错。但我也不明白否决票是什么:D