Question

因此，每次我将数据输入到位于我的AddContacts类中的EditText字段时，我的Dialog说我已经成功添加了信息，但是在日志中它没有说明这样的表：contactsTable。我认为错误是在我的数据库类中的onCreate和onUpdate方法中，但我不知道该怎么做

代码：

package com.example.myfirstapp;

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


public class DatabaseTable {
private static final String TAG = "ContactsDatabase";

//The columns we'll include in the contacts table
public static final String COL_ID = "ID";
public static final String COL_NAME = "NAME";
public static final String COL_EMAIL = "EMAIL";

private static final String DATABASE_NAME = "CONTACT";
private static final String DATABASE_TABLE = "contactsTable";
private static final int DATABASE_VERSION = 1;
private Context ourContext;
private DbHelper DBHelper;
private SQLiteDatabase db;
private static final String DATABASE_CREATE = 
        "CREATE TABLE " + DATABASE_TABLE + " (" +
         COL_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
         COL_NAME + " TEXT NOT NULL, " + 
         COL_EMAIL + " TEXT NOT NULL);";

    private static class DbHelper extends SQLiteOpenHelper {

        DbHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        public void onCreate(SQLiteDatabase db) {
            try {
                db.execSQL(DATABASE_CREATE);
            } catch (SQLException e) {
                e.printStackTrace();
            }
    }

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

        public DatabaseTable(Context context) {
            ourContext = context;
        }

        public DatabaseTable open() throws SQLException {
            DBHelper = new DbHelper(ourContext);
            db = DBHelper.getWritableDatabase();
            return this;
        }

        public void close() {
            DBHelper.close();
        }

        public long insertContact(String name, String email) {
            ContentValues initialValues = new ContentValues();
            initialValues.put(COL_NAME, name);
            initialValues.put(COL_EMAIL, email);
            return db.insert(DATABASE_TABLE, null, initialValues);
        }

        public void deleteRecord(long rowId)
        {
            db.delete(DATABASE_TABLE, COL_ID + "=" + rowId, null);
        }

        public Cursor getAllRecords() {
            return db.query(DATABASE_TABLE, new String[] {COL_ID, COL_NAME, COL_EMAIL}, null, 
                    null, null, null, null);
        }

        public Cursor getRecord(long rowId) throws SQLException {

            Cursor cursor = db.query(true, DATABASE_TABLE, new String[] {COL_ID, COL_NAME,
                    COL_EMAIL}, COL_ID + "=" + rowId, null, null, null, null, null);

            if (cursor != null)
                cursor.moveToFirst();

            return cursor;
            }

        public boolean updateRecord(long rowId, String name, String email) {
            ContentValues content = new ContentValues();
            content.put(COL_NAME, name);
            content.put(COL_EMAIL, email);
            return db.update(DATABASE_TABLE, content, COL_ID + "=" + rowId, null) > 0;
        }

}

Answer 1

您在运行应用程序至少一次后更改了DATABASE_TABLE了吗？如果是这样，您需要更新SQLite架构，最简单的方法是make DATABASE_VERSION = 2;。 Android也非常关注主键，您应该将COL_ID更改为"_id"。

将来，每次更改DATABASE_VERSION声明时都必须增加CREATE_TABLE。否则SQLite将没有当前信息。

SQL Android错误：没有这样的表

1 个答案: