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我正在尝试使用 addPoll 函数将数据添加到多个表中；但是，当我这样做时，应用程序崩溃了。

public void addPoll(String userName, String pollName, String optionName1){
    SQLiteDatabase db = this.getWritableDatabase();
    String userId = getUserId(userName);
    String pollId = getPollId(pollName);


    String query = "INSERT INTO polls SET userId=" + userId + ", pollName=" + pollName;
    String query2 = "INSERT INTO options SET pollId=" + pollId + ", optionName1=" + optionName1;


    db.execSQL(query);
    db.execSQL(query2);

}

我正在按照我在 mysqli 和 php 中执行此操作的方式进行操作；有没有更简单的方法来运行这些查询？

完整的数据库处理程序：

package com.example.votingapp.library;

import java.util.HashMap;

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

public class DatabaseHandler extends SQLiteOpenHelper {

    // All Static variables
    // Database Version
    private static final int DATABASE_VERSION = 2;
    // Database Name
    private static final String DATABASE_NAME = "beta.db";
    // Users table name
    public static final String TABLE_USERS = "users";

    // Users Table Columns names
    private static final String KEY_ID = "userId";
    private static final String KEY_NAME = "userName";
    private static final String KEY_PASS = "userPass";

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

    // Creating Tables
    @Override
    public void onCreate(SQLiteDatabase db) {
        String CREATE_USERS_TABLE = "CREATE TABLE " + TABLE_USERS + "("
                + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
                + KEY_NAME + " TEXT,"
                + KEY_PASS + " TEXT" + ");";


       String CREATE_POLLS_TABLE = "CREATE TABLE polls ( pollId INTEGER PRIMARY KEY  AUTOINCREMENT, pollName TEXT, " +
                "userId INTEGER);";

      String CREATE_OPTIONS_TABLE = "CREATE TABLE options ( optionId INTEGER PRIMARY KEY  AUTOINCREMENT, optionName1 TEXT, optionName2 TEXT, " +
                "optionName3 TEXT, optionName4 TEXT, optionName5 TEXT, pollId INTEGER);";

       db.execSQL(CREATE_USERS_TABLE);
       db.execSQL(CREATE_POLLS_TABLE);
       db.execSQL(CREATE_OPTIONS_TABLE);

    }

    // Upgrading database
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Drop older table if existed
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_USERS);
        db.execSQL("DROP TABLE IF EXISTS polls");
        db.execSQL("DROP TABLE IF EXISTS options");


        // Create tables again
        onCreate(db);
    }






    //Storing user details in database
    public void addUser(String userName, String userPass) {
        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(KEY_NAME, userName); // userName
        values.put(KEY_PASS, userPass); // userPass

        // Inserting Row
        db.insert(TABLE_USERS, null, values);
        db.close(); // Closing database connection
    }

    public void addPoll(String userName, String pollName, String optionName1){
        SQLiteDatabase db = this.getWritableDatabase();
        String userId = getUserId(userName);
        String pollId = getPollId(pollName);


    String query = "INSERT INTO polls SET userId=" + userId + ", pollName=" + pollName;
    String query2 = "INSERT INTO options SET pollId=" + pollId + ", optionName1=" + optionName1;


        db.execSQL(query);
        db.execSQL(query2);

    }

    public String getPollId(String pollName) {
        SQLiteDatabase db = this.getReadableDatabase();

        Cursor c = db.rawQuery("SELECT pollId FROM polls WHERE pollName='" + pollName + "'", null);

        if (c != null ) {
            c.moveToFirst();
            int iPassword = c.getColumnIndex("pollId");
            String pollId = c.getString(iPassword);
            return pollId;
        }else{
            return null;
        }
    }

    public String getUserId(String userName) {
        SQLiteDatabase db = this.getReadableDatabase();

        Cursor c = db.rawQuery("SELECT userId FROM users WHERE userName='" + userName + "'", null);

        if (c != null ) {
            c.moveToFirst();
            int iPassword = c.getColumnIndex("userId");
            String userId = c.getString(iPassword);
            return userId;
        }else{
            return null;
        }
    }



    //Getting user data from database
    public HashMap<String, String> getUserDetails(){
        HashMap<String,String> user = new HashMap<String,String>();
        String selectQuery = "SELECT  * FROM " + TABLE_USERS;

        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);
        // Move to first row
        cursor.moveToFirst();
        if(cursor.getCount() > 0){
            user.put("userName", cursor.getString(1));
            user.put("userPass", cursor.getString(2));
        }
        cursor.close();
        db.close();
        // return user
        return user;
    }

    /**
     * Getting user login status
     * return true if rows are there in table
     * */
    public int getRowCount() {
        String countQuery = "SELECT  * FROM " + TABLE_USERS;
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(countQuery, null);
        int rowCount = cursor.getCount();
        db.close();
        cursor.close();

        // return row count
        return rowCount;
    }

    /**
     * Re crate database
     * Delete all tables and create them again
     * */
    public void resetTables(){
        SQLiteDatabase db = this.getWritableDatabase();
        // Delete All Rows
        db.delete(TABLE_USERS, null, null);
        db.close();
    }

    /**
     * Function get Login status
     * */
    public boolean isUserLoggedIn(Context context){
        DatabaseHandler db = new DatabaseHandler(context);
        int count = db.getRowCount();
        if(count > 0){
            // user logged in
            return true;
        }
        return false;
    }

    /**
     * Function to logout user
     * Reset Database
     * */
    public boolean logoutUser(Context context){
        DatabaseHandler db = new DatabaseHandler(context);
        db.resetTables();
        return true;
    }

}
4

1 回答 1

1

您的 SQL 语法在这里不正确：

String query = "INSERT INTO polls SET userId=" + userId + ", pollName=" + pollName;
String query2 = "INSERT INTO options SET pollId=" + pollId + ", optionName1=" + optionName1;

使用任一

UPDATE table SET ...

如果您正在更新，或者

INSERT INTO table VALUES( ... )

如果您要插入新行。或者更好的是，像你在其他一些方法中一样使用ContentValues和使用。SQLiteDatabase insert()

注意如果您的应用程序出现崩溃问题，最好始终在您的问题中包含 logcat 堆栈跟踪。

于 2013-11-12T11:40:23.710 回答