When does SQLiteOpenHelper onCreate onUpgrade run

Question

I have created my tables in my SQLiteOpenHelper onCreate   but receive  SQLiteException  no such table   or  SQLiteException  no such column   errors  Why      NOTE        This is the amalgamated summary of tens of similar questions every week  Attempting to provide a  canonical  community wiki question answer here so that all those questions can be directed to a good reference

User · Answer

onCreate     When we create DataBase at a first time  i e Database is not exists  onCreate   create database with version which is passed in  SQLiteOpenHelper Context context  String name  SQLiteDatabase CursorFactory factory  int version  onCreate   method is creating the tables you   ve defined and executing any other code you   ve written  However  this method will only be called if the SQLite file is missing in your app   s data directory   data data your apps classpath databases     This method will not be called if you   ve changed your code and relaunched in the emulator   If you want onCreate   to run you need to use adb to delete the SQLite database file    onUpgrade     SQLiteOpenHelper should call the super constructor  The onUpgrade   method will only be called when the version integer is larger than the current version running in the app  If you want the onUpgrade   method to be called  you need to increment the version number in your code

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In my case I get items from XML-file with  lt string-array gt   where I store  lt item gt s  In these  lt item gt s I hold SQL strings and apply one-by-one with databaseBuilder addMigrations migration   I made one mistake  forgot to add   before quote and got the exception   android database sqlite SQLiteException  no such column  some value  code 1 SQLITE ERROR     while compiling  INSERT INTO table name id  name  VALUES 1  some value   So  this is a right variant    lt item gt      INSERT INTO table name id  name  VALUES 1    some value     lt  item gt

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no such table found is mainly when you have not opened the SQLiteOpenHelper class with getwritabledata   and before this you also have to call make constructor with databasename  amp  version   And OnUpgrade is called whenever there is upgrade value in version number given in SQLiteOpenHelper class   Below is the code snippet  No such column found may be because of spell in column name    public class database db       entry data endb      String file name  Record db       SQLiteDatabase sq      public database db Context c                endb new entry data c  file name  null  8             public database db open                 sq endb getWritableDatabase            return this            public Cursor getdata String table                return sq query table  null  null  null  null  null  null             public long insert data String table ContentValues value                return sq insert table  null  value             public void close                 sq close              public void delete String table                sq delete table null null           class entry data extends SQLiteOpenHelper        public entry data Context context  String name  SQLiteDatabase CursorFactory factory                        int version            super context  name  factory  version              TODO Auto-generated constructor stub             Override     public void onCreate SQLiteDatabase sqdb               TODO Auto-generated method stub          sqdb execSQL  CREATE TABLE IF NOT EXISTS  YOUR TABLE NAME  Column 1 text not null Column 2 text not null                  public void onUpgrade SQLiteDatabase db  int oldVersion  int newVersion              onCreate db

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onCreate is called for the first time when creation of tables are needed  We need to override this method where we write the script for table creation which is executed by SQLiteDatabase  execSQL method  After executing in first time deployment  this method will not be called onwards   onUpgrade This method is called when database version is upgraded  Suppose for the first time deployment   database version was 1 and in second deployment there was change in database structure like adding extra column in table  Suppose database version is 2 now

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You can create database  amp  table like   public class DbHelper extends SQLiteOpenHelper   private static final String DBNAME    testdatbase db   private static final int VERSION   1   public DbHelper Context context        super context  DBNAME  null  VERSION          TODO Auto-generated constructor stub     Override public void onCreate SQLiteDatabase db           TODO Auto-generated method stub     db execSQL  create table BookDb id integer primary key autoincrement BookName text Author text IssuedOn text DueDate text Fine text Totalfine text         Override public void onUpgrade SQLiteDatabase db  int oldVersion  int newVersion        db execSQL  DROP TABLE IF EXISTS BookDb        onCreate db           Note   if you want create another table or add columns or no such table  just increment the VERSION

User · Answer

May be I am too late but I would like to share my short and sweet answer  Please check Answer  for a same problem  It will definitely help you  No more deep specifications   If you are confident about syntax for creating table  than it may happen when you add new column in your same table  for that     1  Uninstall from your device and run it again   OR  2  Setting -  app -  ClearData  OR  3  Change DATABASE VERSION in your  DatabaseHandler  class  If you have added new column than it will upgrade automatically   public DatabaseHandler Context context        super context  DATABASE NAME  null  DATABASE VERSION       OR  4  Change DATABASE NAME in your  DatabaseHandler  class  I faced same problem  But I succeed by changing DATABASE NAME

User · Answer

SQLiteOpenHelper onCreate   and onUpgrade   callbacks are invoked when the database is actually opened  for example by a call to getWritableDatabase    The database is not opened when the database helper object itself is created   SQLiteOpenHelper versions the database files  The version number is the int argument passed to the constructor  In the database file  the version number is stored in PRAGMA user version   onCreate   is only run when the database file did not exist and was just created  If onCreate   returns successfully  doesn t throw an exception   the database is assumed to be created with the requested version number  As an implication  you should not catch SQLExceptions in onCreate   yourself   onUpgrade   is only called when the database file exists but the stored version number is lower than requested in the constructor  The onUpgrade   should update the table schema to the requested version   When changing the table schema in code  onCreate     you should make sure the database is updated  Two main approaches    Delete the old database file so that onCreate   is run again  This is often preferred at development time where you have control over the installed versions and data loss is not an issue  Some ways to delete the database file    Uninstall the application  Use the application manager or adb uninstall your package name from the shell  Clear application data  Use the application manager   Increment the database version so that onUpgrade   is invoked  This is slightly more complicated as more code is needed    For development time schema upgrades where data loss is not an issue  you can just use execSQL  DROP TABLE IF EXISTS  lt tablename gt    in to remove your existing tables and call onCreate   to recreate the database  For released versions  you should implement data migration in onUpgrade   so your users don t lose their data

User · Answer

To further add missing points here  as per the request by Jaskey  Database version is stored within the SQLite database file   catch is the constructor  SQLiteOpenHelper Context context  String name  SQLiteDatabase CursorFactory factory  int version    So when the database helper constructor is called with a name  2nd param   platform checks if the database exists or not and if the database exists  it gets the version information from the database file header and triggers the right call back  As already explained in the older answer  if the database with the name doesn t exists  it triggers onCreate   Below explanation explains onUpgrade case with an example   Say  your first version of application had the DatabaseHelper  extending SQLiteOpenHelper  with constructor passing version as 1 and then you provided an upgraded application with the new source code having version passed as 2  then automatically when the DatabaseHelper is constructed  platform triggers onUpgrade by seeing the file already exists  but the version is lower than the current version which you have passed   Now say you are planing to give a third version of application with db version as 3  db version is increased only when database schema is to be modified   In such incremental upgrades  you have to write the upgrade logic from each version incrementally for a better maintainable code  Example pseudo code below    Override public void onUpgrade SQLiteDatabase db  int oldVersion  int newVersion      switch oldVersion        case 1           upgrade logic from version 1 to 2     case 2           upgrade logic from version 2 to 3     case 3           upgrade logic from version 3 to 4        break      default         throw new IllegalStateException                   onUpgrade   with unknown oldVersion     oldVersion           Notice the missing break statement in case 1 and 2  This is what I mean by incremental upgrade   Say if the old version is 2 and new version is 4  then the logic will upgrade the database from 2 to 3 and then to 4  If old version is 3 and new version is 4  it will just run the upgrade logic for 3 to 4

User · Answer

Sqliteopenhelper s method have methods create and upgrade create is used when any table is first time created and upgrade method will called everytime whenever table s number of column is changed

User · Answer

Recheck your query in ur DatabaseHandler DatabaseManager class which ever you have took

User · Answer

If you forget to provide a  name  string as the second argument to the constructor  it creates an  in-memory  database which gets erased when you close the app

User · Answer

Your database name must end with  db also your query strings must have a terminator

User · Answer

Points to remember when extending SQLiteOpenHelper   super context  DBName  null  DBversion   - This should be invoked first line of constructor override onCreate and onUpgrade  if needed  onCreate will be invoked only when getWritableDatabase   or getReadableDatabase   is executed  And this will only invoked once when a DBName specified in the first step is not available  You can add create table query on onCreate method Whenever you want to add new table just change DBversion and do the queries in onUpgrade table or simply uninstall then install the app

User · Answer

Uninstall your application from the emulator or device  Run the app again   OnCreate   is not executed when the database already exists

User · Answer

Sqlite database override two methods   1  onCreate    This method invoked only once when the application is start at first time   So it called only once   2 onUpgrade   This method called when we change the database version then this methods gets invoked It is used for the alter the table structure like adding new column after creating DB Schema

[android] When does SQLiteOpenHelper onCreate() / onUpgrade() run?

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