看了很多关于android使用sqlite数据库的文章，很多都是介绍了数据库的建立和表的建立，而表通常都是只建立一张，而实际情况我们用到的表可能不止一张，那这种情况下我们又该怎么办呢，好了，下面我教大家如何在sqlite数据库中建立多张表。
首先是如何建立数据库和表：
建立一个类继承SQLiteOpenHelper，即：
public class ReaderOpenHelper extends SQLiteOpenHelper
然后添加构造方法：
public ReaderOpenHelper(Context context) {
super(context, "people.db", null, 1);
}
people.db是数据库名字，1是数据库版本。
然后在该类实现以下两个方法：
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("create table readers(renumber integer primary key,rename text,retype text,reage text,rephone text,usename integer,password integer,createtime text)");
db.execSQL("create table books(booknumber integer primary key,bookname text,booktype text,bookeditor text,intime text,incounts integer)");
}
db.execSQL的作用是执行SQL语句，create table readers是创建一个叫readers的表，括号里就是各个字段名和值类型。
这里创建了两张表。另一张叫books
继续实现：
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("drop if table exists readers");
db.execSQL("drop if table exists books");
onCreate(db);
}
执行Sql语句"drop if table exists 表名"
这样你的sqlite数据库和两张表就创建完成了。
接下来再建一个数据库manager类，如：
public class ReaderManager
添加一个构造方法
public ReaderManager(Context conetxt) {
this.context = context;
readerOpenHelper = new ReaderOpenHelper(conetxt);
}
然后添加表的操作方法：
package com.zhou.db;
import java.util.ArrayList;
import java.util.List;
import com.zhou.utils.Books;
import com.zhou.utils.Reader;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
public class ReaderManager {
ReaderOpenHelper readerOpenHelper;
Context context;
public ReaderManager(Context conetxt) {
this.context = context;
readerOpenHelper = new ReaderOpenHelper(conetxt);
}
// 增加读者
public void addSQL(Reader reader) {
SQLiteDatabase db = null;
try {
db = readerOpenHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("renumber", reader.getReNumber());
values.put("rename", reader.getName());
values.put("retype", reader.getSex());
values.put("reage", reader.getAge());
values.put("rephone", reader.getPhoneNumber());
values.put("createtime", reader.getCreateTime());
values.put("usename", reader.getUseName());
values.put("password", reader.getPassword());
db.insert("readers", null, values);
} catch (Exception e) {
// TODO: handle exception
} finally {
db.close();
}
}
// 增加图书
public void bookAddSQL(Books book) {
SQLiteDatabase db = null;
try {
db = readerOpenHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("booknumber", book.getBookNumber());
values.put("bookname", book.getBookName());
values.put("booktype", book.getBookType());
values.put("bookeditor", book.getBookEditer());
values.put("intime", book.getInTime());
values.put("incounts", book.getCount());
db.insert("books", null, values);
} catch (Exception e) {
// TODO: handle exception
} finally {
db.close();
}
}
// 读者查询
public List<Reader> selectSQL() {
List<Reader> list = new ArrayList<Reader>();
SQLiteDatabase db = null;
// 获取一个光标对象
Cursor cursor = null;
try {
db = readerOpenHelper.getReadableDatabase();
cursor = db.query("readers", null, null, null, null, null, null);
Reader reader = null;
while (cursor.moveToNext()) {
reader = new Reader();
reader.setReNumber(cursor.getInt(cursor
.getColumnIndex("renumber")));
reader.setName(cursor.getString(cursor.getColumnIndex("rename")));
reader.setSex(cursor.getString(cursor.getColumnIndex("retype")));
reader.setAge(cursor.getString(cursor.getColumnIndex("reage")));
reader.setPhoneNumber(cursor.getString(cursor
.getColumnIndex("rephone")));
reader.setCreateTime(cursor.getString(cursor
.getColumnIndex("createtime")));
reader.setUseName(cursor.getInt(cursor
.getColumnIndex("usename")));
reader.setPassword(cursor.getInt(cursor
.getColumnIndex("password")));
list.add(reader);
}
} catch (Exception e) {
// TODO: handle exception
} finally {
cursor.close();
db.close();
}
return list;
}
// 图书查询
public List<Books> bookSelectSQL() {
List<Books> list = new ArrayList<Books>();
SQLiteDatabase db = null;
// 获取一个光标对象
Cursor cursor = null;
try {
db = readerOpenHelper.getReadableDatabase();
cursor = db.query("books", null, null, null, null, null, null);
Books book = null;
while (cursor.moveToNext()) {
book = new Books();
book.setBookNumber(cursor.getInt(cursor
.getColumnIndex("booknumber")));
book.setBookName(cursor.getString(cursor
.getColumnIndex("bookname")));
book.setBookType(cursor.getString(cursor
.getColumnIndex("booktype")));
book.setBookEditer(cursor.getString(cursor
.getColumnIndex("bookeditor")));
book.setInTime(cursor.getString(cursor.getColumnIndex("intime")));
book.setCount(cursor.getInt(cursor.getColumnIndex("incounts")));
Log.d("TAGG", cursor.getString(cursor.getColumnIndex("intime")));
list.add(book);
}
} catch (Exception e) {
// TODO: handle exception
} finally {
cursor.close();
db.close();
}
return list;
}
// 读者删除
public void deleteSQL(final long id) {
SQLiteDatabase db = null;
try {
db = readerOpenHelper.getWritableDatabase();
db.delete("readers", "renumber=" + id, null);
} catch (Exception e) {
} finally {
db.close();
}
}
// 读者更新
public void updateData(int id, String name, String sex, String age,
String phoneNumber, int password) {
SQLiteDatabase db = null;
try {
db = readerOpenHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("rename", name);
values.put("retype", sex);
values.put("reage", age);
values.put("rephone", phoneNumber);
values.put("password", password);
db.update("readers", values, "renumber=" + id, null);
} catch (Exception e) {
// TODO: handle exception
} finally {
db.close();
}
}
// public long getCount() {
//
// Cursor cursor = null;
// long count = 0;
// SQLiteDatabase db = null;
// try {
// db = readerOpenHelper.getWritableDatabase();
// cursor = db.query("readers", null, null, null, null, null, null);
//
// if (null != cursor) {
// count = cursor.getCount();
// cursor.close();
// }
// } catch (Exception e) {
// } finally {
//