android - 如果我知道 Java，我需要知道什么才能将 Android 应用程序连接到 SQLite 数据库？

Question

我想学习如何为 Android 和 SQLite 编写数据库。如果我知道 Java，我还需要学习什么才能构建数据库？您可以帮助我的任何其他信息将不胜感激。

score 2 · Accepted Answer

2

您需要了解 SQL、关系数据库和规范化规则。

于 2012-05-06T02:17:37.203 回答

score 2 · Accepted Answer

首先，您需要为服务器上的 SQLite 数据库安装、命名和建立凭据（用户名、密码、主机）。这是与执行此操作所需的 Android 类相关的链接：http: //developer.android.com/reference/android/database/sqlite/package-summary.html

然后你需要了解 JAVA 如何与 SQL 对话。我只熟悉 PHP->SQL，但这里有一个 JAVA->SQL 连接的链接，它看起来与 PHP http://sqlzoo.net/java.htm非常相似。

SQL 语言非常简单。

SELECT是从数据库表中获取行。

INSERT是插入行

UPDATE是更改行中的值（又名字段）

DELETE是删除行

虽然很多人可能会为此对我嗤之以鼻，但我从 SQL 语法（并将 PHP 连接到 SQL）开始：W3CSchools

score 2 · Accepted Answer

基本上，您需要一个 DatabaseHelper 类，DataBaseHelper.class 的示例：

import java.util.ArrayList;

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.SQLiteException;

import android.database.sqlite.SQLiteOpenHelper;
public class DBHelper extends SQLiteOpenHelper{

private String sql;
private SQLiteDatabase db;

//database name
private static final String NAME_DB = "Courses.sql";    

//database version
private static final int VERSION_DB = 1;

//database table name
public static final String COURSES_TABLE = "courses";

//database table columns for N_TABLE
public static final String ID_KEYROW= "_id";
public static final String ID_COURSE= "courseid";
public static final String ID_TITLE = "title";
public static final String ID_INSTRUCTOR = "instructor";
public static final String ID_LENGTH = "length";
public static final String ID_RATING = "rating";
public static final String ID_TOPIC = "topic";
public static final String ID_SUBJECT = "subject";
public static final String ID_DESCRIPTION = "description";  
//private final Context myContext;

public DBHelper(Context context) {
    super(context, NAME_DB, null, VERSION_DB);
    //this.myContext = context;
}
//Creating Table
@Override
public void onCreate(SQLiteDatabase db) 
{
    String CREATE_LOGIN_TABLE = "CREATE TABLE " + COURSES_TABLE + "("
            + ID_KEYROW + " INTEGER PRIMARY KEY AUTOINCREMENT, "
            + ID_COURSE + " TEXT NOT NULL, "
            + ID_TITLE + " TEXT NOT NULL, "
            + ID_INSTRUCTOR + " TEXT NOT NULL, "
            + ID_LENGTH + " TEXT NOT NULL, "
            + ID_RATING + " TEXT NOT NULL, "
            + ID_TOPIC + " TEXT NOT NULL, "
            + ID_SUBJECT + " TEXT NOT NULL, "
            + ID_DESCRIPTION + " TEXT NOT NULL" + ")";
    db.execSQL(CREATE_LOGIN_TABLE);
    /* Other Method for Create DataBase.
    db.execSQL(" CREATE TABLE courses" + "(" + ID_KEYROW + " INTEGER PRIMARY KEY AUTOINCREMENT, " + ID_COURSE + " TEXT NOT NULL, " + ID_TITLE + " TEXT NOT NULL, " + ID_INSTRUCTOR + " TEXT NOT NULL, " + ID_LENGTH + " TEXT NOT NULL, " + ID_RATING + " TEXT NOT NULL, " + ID_TOPIC + " TEXT NOT NULL, " + ID_SUBJECT + " TEXT NOT NULL, " + ID_DESCRIPTION + " TEXT NOT NULL);"
            );*/    
}       

//Updating Database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    db.execSQL("DROP TABLE IF EXISTS " + COURSES_TABLE);
    onCreate(db);
}
//Insert Courses
//public void insertCourses(Integer courseid, String title, String instructor, Integer length, Integer rating, String topic, String subject, String description)
public void insertCourses()
{
    SQLiteDatabase db= this.getWritableDatabase();

    sql="INSERT INTO courses(courseid, title, instructor,  length, rating, topic, subject, description) VALUES ('1', 'Interdisciplinary Care Planning', 'Keith Savell', '60', '4.7', 'Interdisciplinary Care Planning requires members of the Interdisciplinary Treatment Team (IDT) to view the Care Plan as a resident centered collaborative effort - rather than as a staff centered document. Learn how to...', 'Encourage the Interdisciplinary Treatment Team (IDT) to work as a team and view the Care Plan as a resident-centered collaborative effort  to enhance the care and quality of resident life.', 'Interdisciplinary Care Planning requires members of the Interdisciplinary Treatment Team (IDT) to view the Care Plan as a resident centered collaborative effort - rather than as a staff centered document. Learn how to utilize the Care Plan to truly function as a team - working together to enhance the care and quality of resident life.')";
    db.execSQL(sql);
    sql="INSERT INTO courses(courseid, title, instructor,  length, rating, topic, subject, description) VALUES ('2', 'Culture Change: Creating A Climate Of Care...', 'Keith Savell', '60', '5', 'Culture Change ', 'Learn to evaluate and modify the environment to support our residents with cognitive impairment as they age in place.', 'Residents with dementia and delirium are constantly assessing the environment, looking for clues to help them understand where they are, who others around them are, what they are supposed to be doing and what is expected of them.')";
    db.execSQL(sql);
    sql="INSERT INTO courses(courseid, title, instructor,  length, rating, topic, subject, description) VALUES ('3', 'Medical Records Documentation', 'Keith Savell', '60', '5', 'Medical Records Documentation ', 'Encourage the Interdisciplinary Treatment Team (IDT) to work as a team and view the Care Plan as a resident-centered collaborative effort  to enhance the care and quality of resident life.', 'Interdisciplinary Care Planning requires members of the Interdisciplinary Treatment Team (IDT) to view the Care Plan as a resident centered collaborative effort - rather than as a staff centered document. Learn how to utilize the Care Plan to truly function as a team - working together to enhance the care and quality of resident life.')";
    db.execSQL(sql);
    sql="INSERT INTO courses(courseid, title, instructor,  length, rating, topic, subject, description) VALUES ('4', 'Census Challenges', 'Keith Savell', '60', '4.45', 'Creative Solutions to Drive Census ', 'Learn to evaluate and modify the environment to support our residents with cognitive impairment as they age in place.', 'Residents with dementia and delirium are constantly assessing the environment, looking for clues to help them understand where they are, who others around them are, what they are supposed to be doing and what is expected of them.')";
    db.execSQL(sql);
    sql="INSERT INTO courses(courseid, title, instructor,  length, rating, topic, subject, description) VALUES ('5', 'Fall Prevention: Reducing Fall Related Injuries', 'Keith Savell', '60', '5', 'Guidelines for Health Care Providers ', 'Encourage the Interdisciplinary Treatment Team (IDT) to work as a team and view the Care Plan as a resident-centered collaborative effort  to enhance the care and quality of resident life.', 'Interdisciplinary Care Planning requires members of the Interdisciplinary Treatment Team (IDT) to view the Care Plan as a resident centered collaborative effort - rather than as a staff centered document. Learn how to utilize the Care Plan to truly function as a team - working together to enhance the care and quality of resident life.')";
    db.execSQL(sql);
    sql="INSERT INTO courses(courseid, title, instructor,  length, rating, topic, subject, description) VALUES ('6', 'Meaningful Engagement', 'Keith Savell', '60', '5', 'Creating The Failure Free Activity Program ', 'Learn to evaluate and modify the environment to support our residents with cognitive impairment as they age in place.', 'Residents with dementia and delirium are constantly assessing the environment, looking for clues to help them understand where they are, who others around them are, what they are supposed to be doing and what is expected of them.')";
    db.execSQL(sql);
    sql="INSERT INTO courses(courseid, title, instructor,  length, rating, topic, subject, description) VALUES ('7', 'Dementia and Delirium', 'Keith Savell', '60', '4.69', 'The Importance of Accurate Diagnosis and Treatment ', 'Encourage the Interdisciplinary Treatment Team (IDT) to work as a team and view the Care Plan as a resident-centered collaborative effort  to enhance the care and quality of resident life.', 'Interdisciplinary Care Planning requires members of the Interdisciplinary Treatment Team (IDT) to view the Care Plan as a resident centered collaborative effort - rather than as a staff centered document. Learn how to utilize the Care Plan to truly function as a team - working together to enhance the care and quality of resident life.')";
    db.execSQL(sql);
    sql="INSERT INTO courses(courseid, title, instructor,  length, rating, topic, subject, description) VALUES ('8', 'Delirium', 'Keith Savell', '60', '4.69', 'The Importance of Accurate Diagnosis and Treatment ', 'Encourage the Interdisciplinary Treatment Team (IDT) to work as a team and view the Care Plan as a resident-centered collaborative effort  to enhance the care and quality of resident life.', 'Interdisciplinary Care Planning requires members of the Interdisciplinary Treatment Team (IDT) to view the Care Plan as a resident centered collaborative effort - rather than as a staff centered document. Learn how to utilize the Care Plan to truly function as a team - working together to enhance the care and quality of resident life.')";
    db.execSQL(sql);

    //Other Style for Insert record in DB.
    ContentValues values = new ContentValues(); //Here from ContentValues
    values.put("courseid", "9");
    values.put("title", "xxxxxxx Care Planning");
    values.put("instructor", "Keith Savell");
    values.put("length", "60");
    values.put("rating", "4.7");
    values.put("topic", "some topic");
    values.put("subject", "some subject");
    values.put("description", "some description");
    db.insert(COURSES_TABLE, null, values);
}

public ArrayList<Courses> getCourses()
{
    db = getWritableDatabase();
    sql = "SELECT courseid, title, instructor, length, rating, topic, subject, description FROM courses";
    Cursor cursor = db.rawQuery(sql, null);
    ArrayList<Courses> courses = new ArrayList<Courses>();


    while (cursor.moveToNext())
    {
        Courses oCourses=new Courses();

        oCourses.courseid=cursor.getInt(0);
        oCourses.title=cursor.getString(1); //Original Value 0
        oCourses.instructor=cursor.getString(2);
        oCourses.length=cursor.getString(3);
        oCourses.rating=cursor.getString(4);
        oCourses.topic=cursor.getString(5);
        oCourses.subject=cursor.getString(6);
        oCourses.description=cursor.getString(7);
        courses.add(oCourses);          
    }       
    db.close();
    cursor.close();
    return courses;     
}

public ArrayList<Courses> getItem(int position)
{
    db = getWritableDatabase();
    sql = "SELECT courseid, title, instructor, length, rating, topic, subject, description FROM courses";
    Cursor cursor = db.rawQuery(sql, null);
    ArrayList<Courses> courses = new ArrayList<Courses>();


    while (cursor.moveToNext())
    {
        Courses oCourses=new Courses();

        oCourses.courseid=cursor.getInt(0);
        oCourses.title=cursor.getString(1); //Original Value 0
        oCourses.instructor=cursor.getString(2);
        oCourses.length=cursor.getString(3);
        oCourses.rating=cursor.getString(4);
        oCourses.topic=cursor.getString(5);
        oCourses.subject=cursor.getString(6);
        oCourses.description=cursor.getString(7);
        courses.add(oCourses);          
    }
    db.close();
    cursor.close();
    return courses;

}

public int getRowCount() {
    String countQuery = "SELECT * FROM " + COURSES_TABLE;
    SQLiteDatabase db =this.getReadableDatabase();
    Cursor cursor = db.rawQuery(countQuery, null);
    int rowCount = cursor.getCount();
    db.close();
    cursor.close();
    //return row count.
    return rowCount;
}//GetRowCount

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

稍后在您的 Mainclass（或您想要管理数据的活动）中调用 DatabaseHelper.class 的方法，希望这能给您一些想法......

android - 如果我知道 Java，我需要知道什么才能将 Android 应用程序连接到 SQLite 数据库？

3 回答 3

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