java - 如何解决向数据库插入数据时出现SQLiteException错误

Question

所以基本上我很困惑为什么我无法添加任何数据。我基本上是从头开始遵循 YouTube 教程的，但由于某种原因，一个特定的错误非常持久。 (它不允许我添加数据，因此我无法使用它。)

下面是我一直在运行的代码，如果有任何帮助，我们将不胜感激:)当然，如果以前有人问过这个问题，请为我指出正确的方向...我确实尝试先搜索。我可以看到它说 user_table 中没有名为 name 的列，但我不明白的是 youtube 视频中没有这样的步骤并且它工作正常吗？

忘记添加错误

    E/SQLiteLog: (1) table Users_Table has no column named NAME
    E/SQLiteDatabase: Error inserting NAME=Kono
    android.database.sqlite.SQLiteException: table Users_Table has no column named NAME (code 1 SQLITE_ERROR): , while compiling: INSERT INTO Users_Table(NAME) VALUES (?)
        at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
        at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:986)
        at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:593)
        at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:590)
        at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:61)
        at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:33)
        at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1597)
        at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1468)
        at com.example.sqldb.dbHelper.insertData(dbHelper.java:46)
        at com.example.sqldb.MainActivity$2.onClick(MainActivity.java:55)
        at android.view.View.performClick(View.java:7125)
        at android.view.View.performClickInternal(View.java:7102)
        at android.view.View.access$3500(View.java:801)
        at android.view.View$PerformClick.run(View.java:27336)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

XML 布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center_horizontal"
    tools:context=".MainActivity">

    <ListView
        android:id="@+id/usersList"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <EditText
            android:id="@+id/add_name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:hint="Name"/>

        <Button
            android:id="@+id/add_data"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Add"/>

   </LinearLayout>
</LinearLayout>

主要Java代码

package com.example.sqldb;

import androidx.appcompat.app.AppCompatActivity;

import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    dbHelper db;

    Button add_data;
    EditText add_name;
    ListView usersList;

    ArrayList<String> listItem;
    ArrayAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        db = new dbHelper(this);

        listItem = new ArrayList<>();

        add_data = findViewById(R.id.add_data);
        add_name = findViewById(R.id.add_name);
        usersList = findViewById(R.id.usersList);

        viewData();

        usersList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                String text = usersList.getItemAtPosition(1).toString();
                Toast.makeText(MainActivity.this, "" + text, Toast.LENGTH_SHORT).show();
            }
        });

        add_data.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String name = add_name.getText().toString();
                if(!name.equals("") && db.insertData(name)) {
                    Toast.makeText(MainActivity.this, "Data Added", Toast.LENGTH_SHORT).show();
                    add_name.setText("");
                }else {
                    Toast.makeText(MainActivity.this, "Error: Data has not been added!", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }

    private void viewData() {
        Cursor cursor = db.viewData();

        if(cursor.getCount() == 0){
            Toast.makeText(this, "No data to show", Toast.LENGTH_SHORT).show();
        }else{
            while (cursor.moveToNext()){
                listItem.add(cursor.getString(1));
            }

            adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, listItem);
            usersList.setAdapter(adapter);
        }

    }
}

数据库助手类

package com.example.sqldb;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class dbHelper extends SQLiteOpenHelper {

    private static final String DB_NAME = "Users.db";
    private static final String DB_TABLE = "Users_Table";

    //Columns
    private static final String ID = "ID";
    private static final String NAME = "NAME";

    private static final String CREATE_TABLE = "CREATE TABLE " + DB_TABLE + "(" +
            ID + "INTEGER PRIMARY KEY AUTOINCREMENT," +
            NAME + " TEXT " + ")";
    public dbHelper(Context context){
        super(context, DB_NAME, null, 1);

    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        db.execSQL(CREATE_TABLE);
    }


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

        onCreate(db);
    }

    //Method to insert data
    public boolean insertData(String name){
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(NAME, name);

        long result = db.insert(DB_TABLE, null, contentValues);

        return result != -1;// if result = -1 data will not be inserted

    }

    //Method to create view for data
    public Cursor viewData(){
        SQLiteDatabase db = this.getReadableDatabase();
        String query = "Select * from " + DB_TABLE;
        Cursor cursor = db.rawQuery(query, null);

        return cursor;


    }
}

Answer 1

您能否替换下面的代码 fragment 并再次尝试插入:

 public static final String CREATE_TABLE =
                "CREATE TABLE IF NOT EXISTS " + DB_TABLE + "("
                        + ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
                        + NAME + " TEXT"                  
                        + ")";

希望这对您有帮助。