Use ormlite in Android for persistence-helloormlite

Android has built-in SQLite, but the common development language Java is object-oriented, while the database is relational, every conversion between the two is very troublesome (I am not familiar with the SQL language ). Java Web development has a lot of ORM frameworks, but it is troublesome to directly use them on Android. I tried to find the android ORM framework. To tell the truth, there are several more.

Implementation Considerations: androrm Official Website: http://androrm.the-pixelpla.net/ To be honest, I really don't understand this. There are two packages in total. One is the dependency package: Apache commons-lang (2.6) Another is the main package: androrm. Jar cannot be used no matter how it is downloaded...
Then we considered db4o. Official Website: http://www.db4o.com/ According to the official website, Android is supported, but I think the package is a little large, but the speed is a little slow.
The last thing we see is ormlite. Official Website: Follow the Convention below to create an android project in Hello World: helloormlite

Add Folder: libs, copy the two required packages to it. Add reference

Create a model: Hello. Java

 
PackageCN. sdx. model;

ImportCom. j256.ormlite. Field. databasefield;

Public ClassHello {
@ Databasefield (generatedid =True)
IntID;
@ Databasefield
String word;

PublicHello (){
}

@ Override
PublicString tostring (){
Stringbuilder sb =NewStringbuilder ();
SB. append ("ID ="). append (ID );
SB. append (", word ="). append (Word );
ReturnSB. tostring ();
}

}
 

@ Databasefield declares that ID is a database field, generatedid = true declares that ID is auto-incrementing, and then overwrites tostring () to add a datahelper. Java

 
 Package CN. sdx. utils;

 Import Java. SQL. sqlexception;

 Import Android. content. context;
 Import Android. database. SQLite. sqlitedatabase;
 Import Android. util. log;


 Import CN. sdx. model. Hello;

 Import Com. j256.ormlite. Android. apptools. ormlitesqliteopenhelper;
 Import Com. j256.ormlite. Dao. Dao;
 Import Com. j256.ormlite. Support. connectionsource;
 Import Com. j256.ormlite. Table. tableutils;

 Public   Class Datahelper Extends Ormlitesqliteopenhelper {

 Private   Static   Final String database_name = "helloormlite. DB ";
 Private   Static   Final   Int Database_version = 1;
 Private Dao  Null ;

 Public Datahelper (context ){
 Super (Context, database_name, Null , Database_version );
}

@ Override
Public   Void Oncreate (sqlitedatabase dB, connectionsource ){
 Try {
Tableutils. createtable (connectionsource, hello. Class );
} Catch (Sqlexception e ){
Log. E (datahelper. Class . Getname (), "failed to create database", e );
E. printstacktrace ();
}
}

@ Override
 Public  Void Onupgrade (sqlitedatabase dB, connectionsource, Int Arg2,
 Int Arg3 ){
 Try {
Tableutils. droptable (connectionsource, hello. Class , True );
Oncreate (dB, connectionsource );
} Catch (Sqlexception e ){
Log. E (datahelper. Class . Getname (), "failed to update database", e );
E. printstacktrace ();
}
}

@ Override
 Public   Void Close (){
 Super . Close ();
Hellodao = Null ;
}

 Public Dao  Throws Sqlexception {
 If (Hellodao = Null ){
Hellodao = getdao (hello. Class );
}
 Return Hellodao;
}
}

Add a textviewhelloormliteactivity. Java file to the layout file to add database operations. Code As follows:

 Package CN. sdx;

 Import Java. SQL. sqlexception;
 Import Java. util. List;

 Import Com. j256.ormlite. Android. apptools. ormlitebaseactivity;
 Import Com. j256.ormlite. Dao. Dao;

 Import Android. OS. Bundle;
 Import Android. widget. textview;
 Import CN. sdx. model. Hello;
 Import CN. sdx. utils. datahelper;

 Public   Class Helloormliteactivity Extends Ormlitebaseactivity <datahelper> {
 /** Called when the activity is first created.  */  
@ Override
 Public   Void Oncreate (bundle savedinstancestate ){
 Super . Oncreate (savedinstancestate );
Setcontentview (R. layout. Main );
Textview TV = (textview) This . Findviewbyid (R. Id. output );
 Try {
Dao  // Add data  
     For ( Int I = 0; I <2; I ++ ){
Hello = New Hello ("hello" + I );
Hellodao. Create (Hello );
}
TV. settext (TV. gettext () + "\ n" + "added data ");
 //  Query the added data  
 List <Hello> hellos = hellodao. queryforall ();
 For (Hello H: hellos ){
TV. settext (TV. gettext () + "\ n" + H. tostring ());
}
 //  Delete the first data  
 Hellodao. Delete (hellos. Get (0 ));
TV. settext (TV. gettext () + "\ n" + "data deletion completed ");
 //  Re-query data  
 Hellos = hellodao. queryforall ();
 For (Hello H: hellos ){
TV. settext (TV. gettext () + "\ n" + H. tostring ());
}
 // Modify data  
 Hello H1 = hellos. Get (0 );
H1.setword ("this is modified data ");
TV. settext (TV. gettext () + "\ n" + "data modified ");
Hellodao. Update (H1 );
 //  Re-query data  
 Hellos = hellodao. queryforall ();
 For (Hello H: hellos ){
TV. settext (TV. gettext () + "\ n" + H. tostring ());
}

} Catch (Sqlexception e ){
//  Todo auto-generated Catch Block  
 E. printstacktrace ();
}

}
}

The above implementation of database operations related to addition, deletion, and modification, the following is the effect:

Ormlite has very powerful functions. The declaration of model classes is very important. Foreign key constraints and non-empty checks all have relative solutions.