关于android中sqllite对时间的操作
sql 中有时间的类型，date,time,datetime,方便关于记录的维护，下面一个demo演示怎么在每条记录中默认增加时间
源码下载地址 http://www.codes51.com/code/detail_1460.html
1.先是databasehelper类，这里建表保存一本书，包括书名，作者。
package com.chaoyue.sqldemo;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHelper extends SQLiteOpenHelper {
private final static String DATABASE_NAME = "BOOKS.db";
private final static int DATABASE_VERSION = 1;
public final static String TABLE_NAME = "books_table";
public final static String BOOK_ID = "book_id";
public final static String BOOK_NAME = "book_name";
public final static String BOOK_AUTHOR = "book_author";
public DatabaseHelper(Context context) {
// TODO Auto-generated constructor stub
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// 创建table
@Override
public void onCreate(SQLiteDatabase db) {
String sql = "CREATE TABLE " + TABLE_NAME + " (" + BOOK_ID
+ " INTEGER primary key autoincrement, " + BOOK_NAME
+ " text, " + BOOK_AUTHOR + " text, oderdate DATETIME DEFAULT CURRENT_TIMESTAMP );";
db.execSQL(sql);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
String sql = "DROP TABLE IF EXISTS " + TABLE_NAME;
db.execSQL(sql);
onCreate(db);
}
public Cursor select() {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db
.query(TABLE_NAME, null, null, null, null, null, null);
return cursor;
}
// 增加操作
public long insert(String bookname, String author) {
SQLiteDatabase db = this.getWritableDatabase();
/* ContentValues */
ContentValues cv = new ContentValues();
cv.put(BOOK_NAME, bookname);
cv.put(BOOK_AUTHOR, author);
long row = db.insert(TABLE_NAME, null, cv);
return row;
}
// 删除操作
public void delete(int id) {
SQLieDatabase db = this.getWritableDatabase();
String where = BOOK_ID + " = ?";
String[] whereValue = { Integer.toString(id) };
db.delete(TABLE_NAME, where, whereValue);
}
// 修改操作
public void update(int id, String bookname, String author) {
SQLiteDatabase db = this.getWritableDatabase();
String where = BOOK_ID + " = ?";
String[] whereValue = { Integer.toString(id) };
ContentValues cv = new ContentValues();
cv.put(BOOK_NAME, bookname);
cv.put(BOOK_AUTHOR, author);
db.update(TABLE_NAME, cv, where, whereValue);
}
public SQLiteDatabase getDB(){
SQLiteDatabase db = this.getReadableDatabase();
return db;
}
}
2.mainactivity中类简单应用
package com.chaoyue.sqldemo;
import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.util.Log;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DatabaseHelper databaseHelper = new DatabaseHelper(this);
databaseHelper.getDB().delete(DatabaseHelper.TABLE_NAME, null, null);
databaseHelper.insert("a", "aa");
databaseHelper.insert("b", "bb");
databaseHelper.insert("c", "cc");
databaseHelper.insert("d", "dd");
databaseHelper.insert("e", "ee");
databaseHelper.insert("f", "ff");
Cursor cursor = databaseHelper.select();
while (cursor.moveToNext()) {
String name = cursor.getString(cursor.getColumnIndex("book_name"));
String author = cursor.getString(cursor
.getColumnIndex("book_author"));
String oderdate = cursor.getString(cursor
.getColumnIndex("oderdate"));
Log.d("", "chaoyue name=" + name + " author=" + author
+ " oderdate="+oderdate );
}
cursor.close();
}
}
3.关于时间的更多操作与类型可以参考官方文档http://www.sqlite.org/lang_datefunc.html