Question

我是SQL新手，希望我们能帮助我，谢谢你！

我收到此错误

replace

我的logcat

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.ztl.ztlubricant.materialtest/com.ztl.ztlubricant.materialtest.MainActivity}: android.database.sqlite.SQLiteException: near "_productname": syntax error (code 1): , while compiling: CREATE TABLE products(_id INTEGER PRIMARY KEY AUTOINCREMENT _productname TEXT );

这是我的MainActivity

12-05 12:09:40.251 3800-3800/? E/AndroidRuntime: FATAL EXCEPTION: main
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime: Process: com.ztl.ztlubricant.materialtest, PID: 3800
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.ztl.ztlubricant.materialtest/com.ztl.ztlubricant.materialtest.MainActivity}: android.database.sqlite.SQLiteException: near "_productname": syntax error (code 1): , while compiling: CREATE TABLE products(_id INTEGER PRIMARY KEY AUTOINCREMENT _productname TEXT );
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.ActivityThread.access$800(ActivityThread.java:135)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:102)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:136)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5021)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at java.lang.reflect.Method.invokeNative(Native Method)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:515)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:827)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:643)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at dalvik.system.NativeStart.main(Native Method)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:  Caused by: android.database.sqlite.SQLiteException: near "_productname": syntax error (code 1): , while compiling: CREATE TABLE products(_id INTEGER PRIMARY KEY AUTOINCREMENT _productname TEXT );
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1672)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1603)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at com.ztl.ztlubricant.materialtest.MyDBHandler.onCreate(MyDBHandler.java:29)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:252)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at com.ztl.ztlubricant.materialtest.MyDBHandler.databaseToString(MyDBHandler.java:55)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at com.ztl.ztlubricant.materialtest.MainActivity.printDatabase(MainActivity.java:45)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at com.ztl.ztlubricant.materialtest.MainActivity.onCreate(MainActivity.java:28)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.Activity.performCreate(Activity.java:5231)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1090)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.ActivityThread.access$800(ActivityThread.java:135) 
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:102) 
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:136) 
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5021) 
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at java.lang.reflect.Method.invokeNative(Native Method) 
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:515) 
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:827) 
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:643) 
12-05 12:09:40.251 3800-3800/? E/AndroidRuntime:     at dalvik.system.NativeStart.main(Native Method)

我的处理程序

public class MainActivity extends AppCompatActivity {

EditText zubInput;
TextView zubText;
MyDBHandler dbHandler;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    zubInput = (EditText) findViewById(R.id.zubName);
    zubText = (TextView) findViewById(R.id.textView);
    dbHandler = new MyDBHandler(this, null, null, 1);
    printDatabase();
}

public void add(View view) {
    Products product = new Products(zubInput.getText().toString());
    dbHandler.addProduct(product);
    printDatabase();
}

public void delete(View view) {
    String inputText = zubInput.getText().toString();
    dbHandler.deleteProduct(inputText);
    printDatabase();
}


public void printDatabase() {
    String dbString = dbHandler.databaseToString();
    zubText.setText(dbString);
    zubInput.setText(" ");
}




@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

}

并且

public class MyDBHandler extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "products.db";
public static final String TABLE_PRODUCT = "products";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_PRODUCTNAME = "_productname";


public MyDBHandler(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
    super(context, DATABASE_NAME, factory, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
    String query = "CREATE TABLE " + TABLE_PRODUCT + "(" +
            COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT " +
            COLUMN_PRODUCTNAME + " TEXT " +
            ");";
    db.execSQL(query);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS" + TABLE_PRODUCT);
    onCreate(db);
}

public void addProduct(Products product){
    ContentValues values = new ContentValues();
    values.put(COLUMN_PRODUCTNAME, product.get_productname());
    SQLiteDatabase db = getWritableDatabase();
    db.insert(TABLE_PRODUCT, null, values);
    db.close();
}

public void deleteProduct(String productName){
    SQLiteDatabase db = getWritableDatabase();
    db.execSQL("DELETE FROM" + TABLE_PRODUCT + "WHERE" + COLUMN_PRODUCTNAME + "=\"" + productName + "\";");


}

public String databaseToString() {
    String dbString = "";
    SQLiteDatabase db = getWritableDatabase();
    String query = "SELECT * FROM" + TABLE_PRODUCT + "WHERE 1";

    Cursor c = db.rawQuery(query, null);
    c.moveToFirst();

    while (!c.isAfterLast()) {
        if(c.getString(c.getColumnIndex("productname")) != null) {
            dbString += c.getString(c.getColumnIndex("productname"));
            dbString += "\n";
        }
    }

    db.close();
    return dbString;
}

}

尽量提供尽可能多的信息..帮助我！

Answer 1

SQL create table语法错误。

CREATE TABLE products(_id INTEGER PRIMARY KEY AUTOINCREMENT _productname TEXT );

您错过了逗号以分隔每列（此处，在_id列之后，您应添加,。）。

CREATE TABLE products(_id INTEGER PRIMARY KEY AUTOINCREMENT, _productname TEXT );

SQL错误我不太确定

1 个答案: