public class MyDataBaseHelper extends SQLiteOpenHelper { public static final String CREATE_BOOK ="create table Book("+ //primary key 将id列设为主键 autoincrement表示id列是自增长的 "id integer primary key autoincrement,"+ "author text,"+ "price real,"+ "name text)"; public static final String CREATE_CATEGORY ="create table Category("+ "id interger primary key autoincrement,"+ "category_name text,"+ "category_code integer)"; private Context mContext; //Construction method: the first parameter Context, the second parameter database name, the third parameter cursor allows us to return a custom // cursor position when querying data, usually null is passed in, and the fourth parameter is null. The parameters represent the version number of the current library public MyDataBaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) { super (context, name, factory, version); mContext = context; } @Override public void onCreate(SQLiteDatabase db) { //Call execSQL() in SQLiteDatabase to execute the table creation statement db.execSQL( CREATE_BOOK ); db.execSQL(CREATE_CATEGORY); //创建成功 Toast.makeText(mContext,"created success",Toast.LENGTH_SHORT).show(); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { //If the Book and Category tables already exist, delete the table db.execSQL( "drop table if exists Book" ); db.execSQL("drop table if exists Category"); onCreate(db); } }
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context="littlestory.com.sqlitedemo.MainActivity"> <Button android:id="@+id/button1" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="创建数据库" /> <Button android:id="@+id/button2" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="数据增" /> <Button android:id="@+id/button3" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="数据删" /> <Button android:id="@+id/button4" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="数据改" /> <Button android:id="@+id/button5" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="数据查" /> <TextView android:id="@+id/tv_text" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="shuju"/> </LinearLayout>
package littlestory.com.sqlitedemo; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.TextView; public class MainActivity extends AppCompatActivity { private MyDataBaseHelper dbHelper; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); dbHelper=new MyDataBaseHelper(this,"BookStore.db",null,1); Button button1= (Button) findViewById(R.id.button1); button1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { dbHelper.getWritableDatabase(); } }); //数据增加 Button button2= (Button) findViewById(R.id.button2); button2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { SQLiteDatabase db=dbHelper.getWritableDatabase(); ContentValues values=new ContentValues(); values.put("name","The Da Vinci Code"); values.put("price",20); values.put("pages",60); values.put("author","Scott"); db.insert("Book",null,values); values.clear(); values.put("name","The Lost Symbol"); values.put("author","Scott"); values.put("pages",500); values.put("price",30); db.insert("Book",null,values); } }); //数据修改 Button button4= (Button) findViewById(R.id.button4); button4.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { SQLiteDatabase db=dbHelper.getWritableDatabase(); ContentValues values=new ContentValues(); values.put("price",19.9); //仔细update中提示的参数（String table,ContentValues,String whereClause,String[] whereArgs） //第三滴四行指定具体更新那几行。注意第三个参数中的？是一个占位符，通过第四个参数为第三个参数中占位符指 // 定相应的内容。 db.update("Book",values,"name=?",new String[]{"The Da Vinci Code"}); } }); //删除数据 //delete(String table, String whereClause, String [] whereArgs) //举个例子 delete(“Book”,”name=?”,new String[] {“The Da Vinci Code”}); //就是把名字为The Da Vinci Code 这本书的数据都删除。 //再比如：delete(“Book”,”price > ?”,new String[] {“20”}); //意思就是把价格大于20 的所有的书都删掉。 //哈哈还是很好玩的，想删什么删什么，但是要注意了 如果你第二，第三个参数不指定的话，就会删除所有行。 //查询数据 // query(String table , String [] columns , String selection , String [] selectionArgs , String groupBy , String having , String orderBy ); // table —指定查询的表名 // columns —指定查询的列名 // selection —指定where的约束条件 // selectionArgs — 为where中的占位符提供具体的值 // groupBy — 指定需要 groupBy 的列 // having — 对groupBy后的结果进一步约束 // orderBy — 指定查询结果的排序方式 Button button5= (Button) findViewById(R.id.button5); TextView tv_text= (TextView) findViewById(R.id.tv_text); button5.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { SQLiteDatabase db=dbHelper.getWritableDatabase(); //指明去查询Book表 Cursor cursor=db.query("Book",null,null,null,null,null,null); //调用moveToFirst()将数据指针移动到第一行的位置。 if(cursor.moveToFirst()){ do{ //然后通过Cursor的getColumnIndex()获取某一列中所对应的位置的索引 String name = cursor.getString(cursor.getColumnIndex("name")); String author= cursor.getString(cursor.getColumnIndex("author")); int pages =cursor.getInt(cursor.getColumnIndex("pages")); double price = cursor.getDouble(cursor.getColumnIndex("pricce")); }while (cursor.moveToNext()); } cursor.close(); } }); } }