Question

我正在尝试将Date in String格式保存在数据库中，但它总是返回-1。为什么会这样？

public boolean addDate(String item1) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL1, item1);

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

        //if date as inserted incorrectly it will return -1
        if (result == -1) {
            return false;
        } else {
            return true;
        }
    }

这是DataBaseHelper类 -

package com.exemple.myapplication;

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

/**
 * Created by Mitch on 2016-05-13.
 */
public class DatabaseHelper extends SQLiteOpenHelper {

    public static final String DATABASE_NAME = "mylist.db";
    public static final String TABLE_NAME = "mylist_data";
    public static final String COL1 = "Date";
    public static final String COL2 = "Distance";
    public static final String COL3 = "Time";


    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String createTable = "CREATE TABLE " + TABLE_NAME + " (ID INTEGER PRIMARY KEY AUTOINCREMENT, " +
                " ITEM1 TEXT)";
        db.execSQL(createTable);
    }

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

    public boolean addDate(String item1) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL1, item1);

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

        //if date as inserted incorrectly it will return -1
        if (result == -1) {
            return false;
        } else {
            return true;
        }
    }
    public boolean addDis(String item1) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL2, item1);

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

        //if date as inserted incorrectly it will return -1
        if (result == -1) {
            return false;
        } else {
            return true;
        }
    }
    public boolean addTime(String item1) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL3, item1);

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

        //if date as inserted incorrectly it will return -1
        if (result == -1) {
            return false;
        } else {
            return true;
        }
    }
    public Cursor getListContents(){
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor data = db.rawQuery("SELECT * FROM " + TABLE_NAME, null);
        return data;
    }
}

Answer 1

您的表格中没有名为 <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <class name="hibernate.Person" table="PEOPLES"> <id name="id" column="ID"> <generator class="foreign"> <param name="property">adress</param> </generator> </id> <property name="name" /> <one-to-one name="adress" cascade="persist, delete"/> </class> </hibernate-mapping>的列（也不是Date或Distance。您需要更改Time语句以包含以下列：

CREATE TABLE

这假设所有列都是String createTable = "CREATE TABLE " + TABLE_NAME + " (ID INTEGER PRIMARY KEY AUTOINCREMENT, " + COL1 + " TEXT, " + COL2 + " TEXT, " + COL3 + " TEXT, " + "ITEM1 TEXT)";类型，并且您仍然需要列TEXT。如果没有，则只需删除该行并在ITEM1之后关闭括号。

Answer 2

这是因为您使用COL1作为密钥，但等于="Date"，但表mylist_data只包含一个名为"ITEM1"的列，因此请将COL1 = "Date"替换为{ {1}}。

将值插入Sql数据库

2 个答案: