Android SQL statement to implement database additions and deletions

This article describes the database additions and deletions in Android

Review SQL Syntax:

* Increase

Insert into info (name,phone) VALUES (' Wuyudong ', ' 111 ')

* Delete

Delete from person where name = ' Wuyudong '

* Change

Update person set number= ' 119 ' where name= ' Wuyudong '

* Check

SELECT * FROM person

SELECT * FROM person where name= ' Wuyudong '

The database file is in the/data/data/package name/databases/xxx.db

The following uses the code to complete the related operation

First define a person class

PackageCom.wuyudong.db.domain;PublicClassperson {PrivateIntIdPrivateString name;PrivateString number;PublicPerson () {}Public person (IntID, string name, string number) {This.id =IdTHIS.name =NameThis.number =Number }PublicIntGetId () {ReturnId }Publicvoid SetId (IntID) {this.id = ID;} public String getName () { return name;} public void setName (String name) { this.name = name;} public String GetNumber () { return number ;} public void Setnumber (String number) { this.number = number ;}}     

Then implement the code for the relevant operation:

PackageCom.wuyudong.db.dao;ImportJava.util.ArrayList;ImportJava.util.List;ImportAndroid.content.Context;ImportAndroid.database.Cursor;ImportAndroid.database.sqlite.SQLiteDatabase;ImportCom.wuyudong.db.PersonSQLiteOpenHelper;ImportCom.wuyudong.db.domain.Person;PublicClassPersondao {PrivatePersonsqliteopenhelper Helper;PublicPersondao (Context context) {helper =NewPersonsqliteopenhelper (context); }/*** Add a record to the database * *@paramName * Name *@paramNumber * Phone*/PublicvoidAdd (string name, string number) {Sqlitedatabase db =Helper.getwritabledatabase (); Db.execsql ("INSERT into person (name,number) VALUES (?,?)",NewObject[] {name, number}); Db.close (); }/*** Query record is present * *@paramName * Name return true exists, false does not exist*/PublicBooleanFind (String name) {Sqlitedatabase db =Helper.getreadabledatabase (); cursor cursor = db.rawquery ("select * from person where name=?"),NewString[] {name});Boolean result =Cursor.movetonext (); Cursor.close (); Db.close ();ReturnResult }/*** *@paramName * Names of persons to be modified *@paramNewnumber * New Number*/PublicvoidUpdate (string name, String newnumber) {Sqlitedatabase db =Helper.getreadabledatabase (); Db.execsql ("Update person set number=?") Where Name=? ",NewObject[]{newnumber,name}); Db.close (); }/*** Delete a record *@paramName*/PublicvoidDelete (String name) {Sqlitedatabase db =Helper.getreadabledatabase (); Db.execsql ("Delete from person where name=?",NewObject[]{name}); Db.close (); }/*** Return all database information *@return*/Public list<person>FindAll () {list<person> persons =New arraylist<person>(); Sqlitedatabase db = helper.getreadabledatabase (); cursor cursor = db.rawquery ("SELECT * from person", null); while (Cursor.movetonext ()) { int id = cursor.getint (cursor.getcolumnindex ("id")); String name = cursor.getstring (Cursor.getcolumnindex ("name")); String number = cursor.getstring (Cursor.getcolumnindex ("number")); Person person = New person (ID, name, number); Persons.add (person);} cursor.close (); Db.close (); return Persons;}}             

The complete test code is as follows:

PackageCom.wuyudong.db.test;ImportJava.util.List;ImportCom.wuyudong.db.PersonSQLiteOpenHelper;ImportCom.wuyudong.db.dao.PersonDao;ImportCom.wuyudong.db.domain.Person;ImportAndroid.database.sqlite.SQLiteDatabase;ImportAndroid.test.AndroidTestCase;PublicClass TestpersondbExtendsAndroidtestcase {Publicvoid Testcreatedb ()ThrowsException {Personsqliteopenhelper helper =NewPersonsqliteopenhelper (GetContext ()); Sqlitedatabase db =Helper.getwritabledatabase (); }Publicvoid Testadd ()ThrowsException {Persondao DAO =NewPersondao (GetContext ()); Dao.add ("Wuyudong", "666"); }Publicvoid Testfind ()ThrowsException {Persondao DAO =NewPersondao (GetContext ());Boolean result = Dao.find ("Zhangsan"); Assertequals (True, result); }Publicvoid Testupdate ()ThrowsException {Persondao DAO =NewPersondao (GetContext ()); Dao.update ("Zhangsan", "655"); } public void Testdelete () throws Exception {Persondao dao = new Persondao (GetContext ()); Dao.delete ("Zhangsan" ) ; } public void Testfindall () throws Exception {Persondao dao = new Persondao (GetContext ()); list<person> persons = Dao.findall (); for 

Android SQL statement to implement database additions and deletions