问题
I'm using prepopulated sqlite database in my app and i'm trying to update my database in my android application but the onUpgrade method doesn't get called when I increment the version number. i tried googling, searched on stackoverflow but nothing helped. if I uncomment this.getReadableDatabase() in my constructor the onUpgrade method gets called but I can't query the data and returns error.
Here is my code.
public class DatabaseHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "dictionary.db";
private static final int DB_VERSION = 1;
private String DB_PATH = null;
private static final String TABLE_DICTIONARY = "dictionary";
private static final String TABLE_BOOKMARK= "bookmark";
private static final String COL_ID = "id";
private static final String COL_WORD = "word";
private static final String COL_DEFINITION = "definition";
private Context mcontext;
private SQLiteDatabase mDatabase;
public DatabaseHelper( Context context) {
super(context, DB_NAME, null, DB_VERSION);
this.mcontext = context;
this.DB_PATH = "/data/data/" + context.getPackageName() + "/" + "databases/";
//this.getReadableDatabase();
}
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (!dbExist) {
this.getReadableDatabase();
try {
mcontext.deleteDatabase(DB_NAME);
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
public boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DB_NAME;
checkDB = SQ
LiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
} catch (SQLiteException e) {
e.printStackTrace();
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
private void copyDataBase() throws IOException {
InputStream myInput = mcontext.getAssets().open(DB_NAME);
String outFileName = DB_PATH + DB_NAME;
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDatabase() throws SQLException {
String myPath = DB_PATH + DB_NAME;
mDatabase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}
@Override
public synchronized void close() {
if (mDatabase != null)
mDatabase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (newVersion > oldVersion) {
try {
copyDataBase();
} catch (IOException e) {
e.printStackTrace();
}
}
Log.d(TAG, "onUpgrade:called ");
}
}
回答1:
I believe that your issue is that you don't use one of the SQLiteOpenHelper's methods (getWritableDatabse or getReadableDatabase) to open the database.
Rather you use the SQLiteDatabase's OPEN method. Which doesn't do the version check and set.
If I uncomment this.getReadableDatabase() in my constructor the onUpgrade method gets called but I can't query the data and returns error.
Introducing the getReadableDatabase, then does the check and attempts to copy the newer version, but the older version is open and so you likely get a conflict as a result.
You may find the answers to the question Which methods can be used to manage differing versions of pre-existing databases? helpful (perhaps the 2nd).
Working Example
The following working example utilises the code from the linked answer but is based upon the code and database from the question (as is ascertainable).
The core underlying class is DatabaseAssetHandler.java, which includes a number of static methods for checking and copying the database, all notably as a file rather than as an SQLite database.
A subclass of SQLiteOpenHelper, based upon the question's DatabaseHelper.java class but utilising the DatabaseAssethandler methods to check the coded version againast the database file version (negating the need to use the onUpgrade method and also the onCreate method)
Finally the example includes an Activity, MainActivity.java as you'd typically find. This class additionally extracts all rows from the database and dumps the Cursor to the log.
DatabaseAssetManager.java
public class DatabaseAssetHandler {
static final String[] tempfiles = new String[]{"-journal","-wal","-shm"}; // temporary files to rename
public static final String backup = "-backup"; //value to be appended to file name when renaming (psuedo delete)
public static final int OUCH = -666666666;
/**
* Check if the database already exists. NOTE will create the databases folder is it doesn't exist
* @return true if it exists, false if it doesn't
*/
public static boolean checkDataBase(Context context, String dbname) {
File db = new File(context.getDatabasePath(dbname).getPath()); //Get the file name of the database
Log.d("DBPATH","DB Path is " + db.getPath()); //TODO remove if publish App
if (db.exists()) return true; // If it exists then return doing nothing
// Get the parent (directory in which the database file would be)
File dbdir = db.getParentFile();
// If the directory does not exits then make the directory (and higher level directories)
if (!dbdir.exists()) {
db.getParentFile().mkdirs();
dbdir.mkdirs();
}
return false;
}
/**
* Copy database file from the assets folder
* (long version caters for asset file name being different to the database name)
* @param context Context is needed to get the applicable package
* @param dbname name of the database file
* @param assetfilename name of the asset file
* @param deleteExistingDB true if an existing database file should be deleted
* note will delete journal and wal files
* note doen't actually delete the files rater it renames
* the files by appended -backup to the file name
* SEE/USE clearForceBackups below to delete the renamed files
*/
public static void copyDataBase(Context context, String dbname, String assetfilename, boolean deleteExistingDB, int version) {
checkpointIfWALEnabled(context,dbname);
final String TAG = "COPYDATABASE";
int stage = 0, buffer_size = 4096, blocks_copied = 0, bytes_copied = 0;
File f = new File(context.getDatabasePath(dbname).toString());
InputStream is;
OutputStream os;
/**
* If forcing then effectively delete (rename) current database files
*/
if (deleteExistingDB) {
f.renameTo(context.getDatabasePath(dbname + backup));
for (String s: tempfiles) {
File tmpf = new File(context.getDatabasePath(dbname + s).toString());
if (tmpf.exists()) {
tmpf.renameTo(context.getDatabasePath(dbname + s + backup));
}
}
}
//Open your local db as the input stream
Log.d(TAG,"Initiated Copy of the database file " + assetfilename + " from the assets folder."); //TODO remove if publishing
try {
is = context.getAssets().open(assetfilename); // Open the Asset file
stage++;
Log.d(TAG, "Asset file " + assetfilename + " found so attmepting to copy to " + f.getPath()); //TODO remove if publishing
os = new FileOutputStream(f);
stage++;
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[buffer_size];
int length;
while ((length = is.read(buffer)) > 0) {
blocks_copied++;
Log.d(TAG, "Attempting copy of block " + String.valueOf(blocks_copied) + " which has " + String.valueOf(length) + " bytes."); //TODO remove if publishing
os.write(buffer, 0, length);
bytes_copied += length;
}
stage++;
Log.d(TAG,
"Finished copying Database " + dbname +
" from the assets folder, to " + f.getPath() +
String.valueOf(bytes_copied) + "were copied, in " +
String.valueOf(blocks_copied) + " blocks of size " +
String.valueOf(buffer_size) + "."
); //TODO remove if publishing
//Close the streams
os.flush();
stage++;
os.close();
stage++;
is.close();
Log.d(TAG, "All Streams have been flushed and closed.");
if (version > 0) {
setVersion(context,dbname,version);
}
} catch (IOException e) {
String exception_message = "";
e.printStackTrace();
switch (stage) {
case 0:
exception_message = "Error trying to open the asset " + dbname;
break;
case 1:
exception_message = "Error opening Database file for output, path is " + f.getPath();
break;
case 2:
exception_message = "Error flushing written database file " + f.getPath();
break;
case 3:
exception_message = "Error closing written database file " + f.getPath();
break;
case 4:
exception_message = "Error closing asset file " + f.getPath();
}
throw new RuntimeException("Unable to copy the database from the asset folder." + exception_message + " see starck-trace above.");
}
}
/**
* Copy the databsse from the assets folder where asset name and dbname are the same
* @param context
* @param dbname
* @param deleteExistingDB
*/
public static void copyDataBase(Context context, String dbname, boolean deleteExistingDB, int version) {
copyDataBase(context, dbname,dbname,deleteExistingDB, version);
}
/**
* Get the SQLite_user_vesrion from the DB in the asset folder
*
* @param context needed to get the appropriate package assets
* @param assetfilename the name of the asset file (assumes/requires name matches database)
* @return the version number as stored in the asset DB
*/
public static int getVersionFromDBInAssetFolder(Context context, String assetfilename) {
InputStream is;
try {
is = context.getAssets().open(assetfilename);
} catch (IOException e) {
return OUCH;
}
return getDBVersionFromInputStream(is);
}
/**
* Get the version from the database itself without opening the database as an SQliteDatabase
* @param context Needed to ascertain package
* @param dbname the name of the dataabase
* @return the version number extracted
*/
public static int getVersionFromDBFile(Context context, String dbname) {
InputStream is;
try {
is = new FileInputStream(new File(context.getDatabasePath(dbname).toString()));
} catch (IOException e) {
return OUCH;
}
return getDBVersionFromInputStream(is);
}
/**
* Get the Database Version (user_version) from an inputstream
* Note the inputstream is closed
* @param is The Inputstream
* @return The extracted version number
*/
private static int getDBVersionFromInputStream(InputStream is) {
int rv = -1, dbversion_offset = 60, dbversion_length = 4 ;
byte[] dbfileheader = new byte[64];
byte[] dbversion = new byte[4];
try {
is.read(dbfileheader);
is.close();
} catch (IOException e) {
e.printStackTrace();
return rv;
}
for (int i = 0; i < dbversion_length; i++ ) {
dbversion[i] = dbfileheader[dbversion_offset + i];
}
return ByteBuffer.wrap(dbversion).getInt();
}
/**
* Check to see if the asset file exists
*
* @param context needed to get the appropriate package
* @param assetfilename the name of the asset file to check
* @return true if the asset file exists, else false
*/
public static boolean ifAssetFileExists(Context context, String assetfilename) {
try {
context.getAssets().open(assetfilename);
} catch (IOException e) {
return false;
}
return true;
}
/**
* Delete the backup
* @param context
* @param dbname
*/
public static void clearForceBackups(Context context, String dbname) {
String[] fulllist = new String[tempfiles.length + 1];
for (int i = 0;i < tempfiles.length; i++) {
fulllist[i] = tempfiles[i];
}
fulllist[tempfiles.length] = ""; // Add "" so database file backup is also deleted
for (String s: fulllist) {
File tmpf = new File(context.getDatabasePath(dbname + s + backup).toString());
if (tmpf.exists()) {
tmpf.delete();
}
}
}
/**
*
* @param context The context so that the respective package is used
* @param dbname The name of the database (the old will have -backup appended)
* @param table The table from which to copy the data
*/
public static void restoreTable(Context context, String dbname, String table) {
ContentValues cv = new ContentValues();
SQLiteDatabase dbnew = SQLiteDatabase.openDatabase(context.getDatabasePath(dbname).toString(), null,SQLiteDatabase.OPEN_READWRITE);
SQLiteDatabase dbold = SQLiteDatabase.openDatabase(context.getDatabasePath(dbname + backup).toString(),null,SQLiteDatabase.OPEN_READONLY);
Cursor csr = dbold.query(table,null,null,null,null,null,null);
dbnew.beginTransaction();
while (csr.moveToNext()) {
cv.clear();
int offset = 0;
for (String column: csr.getColumnNames()) {
switch (csr.getType(offset++)){
case Cursor.FIELD_TYPE_NULL:
break;
case Cursor.FIELD_TYPE_INTEGER:
cv.put(column,csr.getLong(csr.getColumnIndex(column)));
break;
case Cursor.FIELD_TYPE_FLOAT:
cv.put(column,csr.getFloat(csr.getColumnIndex(column)));
break;
case Cursor.FIELD_TYPE_STRING:
cv.put(column,csr.getString(csr.getColumnIndex(column)));
break;
case Cursor.FIELD_TYPE_BLOB:
cv.put(column,csr.getBlob(csr.getColumnIndex(column)));
}
}
dbnew.insert(DatabaseHelper.TABLE_BOOKMARK,null,cv);
}
dbnew.setTransactionSuccessful();
dbnew.endTransaction();
csr.close();
dbnew.close();
dbold.close();
}
private static void checkpointIfWALEnabled(Context context, String dbname) {
final String TAG = "WALCHKPNT";
Cursor csr;
int wal_busy = -99, wal_log = -99, wal_checkpointed = -99;
if (!new File(context.getDatabasePath(dbname).getPath()).exists()) {
return;
}
SQLiteDatabase db = SQLiteDatabase.openDatabase(context.getDatabasePath(dbname).getPath(),null,SQLiteDatabase.OPEN_READWRITE);
csr = db.rawQuery("PRAGMA journal_mode",null);
if (csr.moveToFirst()) {
String mode = csr.getString(0);
//Log.d(TAG, "Mode is " + mode);
if (mode.toLowerCase().equals("wal")) {
csr = db.rawQuery("PRAGMA wal_checkpoint",null);
if (csr.moveToFirst()) {
wal_busy = csr.getInt(0);
wal_log = csr.getInt(1);
wal_checkpointed = csr.getInt(2);
}
//Log.d(TAG,"Checkpoint pre checkpointing Busy = " + String.valueOf(wal_busy) + " LOG = " + String.valueOf(wal_log) + " CHECKPOINTED = " + String.valueOf(wal_checkpointed) );
csr = db.rawQuery("PRAGMA wal_checkpoint(TRUNCATE)",null);
csr.getCount();
csr = db.rawQuery("PRAGMA wal_checkpoint",null);
if (csr.moveToFirst()) {
wal_busy = csr.getInt(0);
wal_log = csr.getInt(1);
wal_checkpointed = csr.getInt(2);
}
//Log.d(TAG,"Checkpoint post checkpointing Busy = " + String.valueOf(wal_busy) + " LOG = " + String.valueOf(wal_log) + " CHECKPOINTED = " + String.valueOf(wal_checkpointed) );
}
}
csr.close();
db.close();
}
private static void setVersion(Context context, String dbname, int version) {
SQLiteDatabase db = SQLiteDatabase.openDatabase(context.getDatabasePath(dbname).getPath(),null,SQLiteDatabase.OPEN_READWRITE);
db.setVersion(version);
db.close();
}
}
- Note that not all methods are utilised.
- Note modified (2019-05-08) to specifically set the version number after the copy of the asset file call to new setVersion method.
- Note modified (2019-05-08) to call the new checkpointIfWALEnabled method prior to the copy, so that the database is checkpointed.
DatabaseHelper.java
public class DatabaseHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "dictionary.db";
private static final int DB_VERSION = 1;
//private String DB_PATH = null; //<<<<<<<<<< NOT NEEDED
public static final String TABLE_DICTIONARY = "dictionary";
public static final String TABLE_BOOKMARK= "bookmark";
public static final String COL_ID = "id";
public static final String COL_WORD = "word";
public static final String COL_DEFINITION = "definition";
public Context mcontext;
public SQLiteDatabase mDatabase;
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
this.mcontext = context;
Log.d("DBVERSION","The Database Version (as hard coded) is " + String.valueOf(DB_VERSION));
int dbversion = DatabaseAssetHandler.getVersionFromDBFile(context,DB_NAME);
Log.d("DBVERSION","The Database Version (as per the database file) is " + String.valueOf(dbversion));
// Copy the Database if no database exists
if (!DatabaseAssetHandler.checkDataBase(context,DB_NAME)) {
DatabaseAssetHandler.copyDataBase(context,DB_NAME,true,DB_VERSION);
} else {
if (DB_VERSION > dbversion && DatabaseAssetHandler.checkDataBase(context, DB_NAME)) {
DatabaseAssetHandler.copyDataBase(context, DB_NAME, true,DB_VERSION);
DatabaseAssetHandler.clearForceBackups(context, DB_NAME); // Clear the backups
}
}
mDatabase = this.getWritableDatabase(); //<<<<<<<<<<<<<
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
public void openDatabase() throws SQLException {
mDatabase = this.getWritableDatabase();
}
@Override
public synchronized void close() {
if (mDatabase != null)
mDatabase.close();
super.close();
}
}
- Note modified (2019-05-08) to pass the version number to the copyDatabase method.
MainActivity.java
public class MainActivity extends AppCompatActivity {
DatabaseHelper mDBHlpr;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDBHlpr = new DatabaseHelper(this);
Cursor csr = mDBHlpr.getWritableDatabase().query(
DatabaseHelper.TABLE_DICTIONARY,
null,null,null,null,null,null
);
DatabaseUtils.dumpCursor(csr);
csr.close();
}
}
Results
First a database was created using an external tool with 2 rows in the dictionary table and copied into the assets folder.
Run 1.
The first run, copies the database from the assets folder and results in the log containing :-
04-17 19:24:54.249 3233-3233/m.example.so55711282dictionary D/DBVERSION: The Database Version (as hard coded) is 1
04-17 19:24:54.249 3233-3233/m.example.so55711282dictionary D/DBVERSION: The Database Version (as per the database file) is -666666666
04-17 19:24:54.249 3233-3233/m.example.so55711282dictionary D/DBPATH: DB Path is /data/data/m.example.so55711282dictionary/databases/dictionary.db
04-17 19:24:54.250 3233-3233/m.example.so55711282dictionary D/COPYDATABASE: Initiated Copy of the database file dictionary.db from the assets folder.
04-17 19:24:54.251 3233-3233/m.example.so55711282dictionary D/COPYDATABASE: Asset file dictionary.db found so attmepting to copy to /data/data/m.example.so55711282dictionary/databases/dictionary.db
04-17 19:24:54.251 3233-3233/m.example.so55711282dictionary D/COPYDATABASE: Attempting copy of block 1 which has 4096 bytes.
04-17 19:24:54.251 3233-3233/m.example.so55711282dictionary D/COPYDATABASE: Attempting copy of block 2 which has 4096 bytes.
04-17 19:24:54.251 3233-3233/m.example.so55711282dictionary D/COPYDATABASE: Attempting copy of block 3 which has 4096 bytes.
04-17 19:24:54.251 3233-3233/m.example.so55711282dictionary D/COPYDATABASE: Finished copying Database dictionary.db from the assets folder, to /data/data/m.example.so55711282dictionary/databases/dictionary.db12288were copied, in 3 blocks of size 4096.
04-17 19:24:54.251 3233-3233/m.example.so55711282dictionary D/COPYDATABASE: All Streams have been flushed and closed.
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: >>>>> Dumping cursor android.database.sqlite.SQLiteCursor@22ee92e7
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: 0 {
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: id=1
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: word=Apple
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: definition=Thing that drops from an Apple Tree.
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: }
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: 1 {
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: id=2
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: word=Bucket
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: definition=Hand held container with carrying hanlde.
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: }
04-17 19:24:54.273 3233-3233/m.example.so55711282dictionary I/System.out: <<<<<
i.e. The database has been copied from the assets folder and the expected rows have been dumped.
Run 2
Without making any changes the App was rerun (to test that it doesn't recopy the database) :- This time the logcat contains :-
04-17 19:30:57.444 3343-3343/? D/DBVERSION: The Database Version (as hard coded) is 1
04-17 19:30:57.445 3343-3343/? D/DBVERSION: The Database Version (as per the database file) is 1
04-17 19:30:57.445 3343-3343/? D/DBPATH: DB Path is /data/data/m.example.so55711282dictionary/databases/dictionary.db
04-17 19:30:57.449 3343-3343/? I/System.out: >>>>> Dumping cursor android.database.sqlite.SQLiteCursor@22ee92e7
04-17 19:30:57.449 3343-3343/? I/System.out: 0 {
04-17 19:30:57.449 3343-3343/? I/System.out: id=1
04-17 19:30:57.449 3343-3343/? I/System.out: word=Apple
04-17 19:30:57.450 3343-3343/? I/System.out: definition=Thing that drops from an Apple Tree.
04-17 19:30:57.450 3343-3343/? I/System.out: }
04-17 19:30:57.450 3343-3343/? I/System.out: 1 {
04-17 19:30:57.450 3343-3343/? I/System.out: id=2
04-17 19:30:57.450 3343-3343/? I/System.out: word=Bucket
04-17 19:30:57.450 3343-3343/? I/System.out: definition=Hand held container with carrying hanlde.
04-17 19:30:57.450 3343-3343/? I/System.out: }
04-17 19:30:57.450 3343-3343/? I/System.out: <<<<<
i.e. the database, as it exists, has not been copied.
Run 3.
The database has been modified by adding another two rows using an external tool and then copied into the assets folder replacing the older database file and DB_VERSION is changed to 2.
The log contains :-
04-17 19:35:16.661 3459-3459/m.example.so55711282dictionary D/DBVERSION: The Database Version (as hard coded) is 2
04-17 19:35:16.661 3459-3459/m.example.so55711282dictionary D/DBVERSION: The Database Version (as per the database file) is 1
04-17 19:35:16.661 3459-3459/m.example.so55711282dictionary D/DBPATH: DB Path is /data/data/m.example.so55711282dictionary/databases/dictionary.db
04-17 19:35:16.661 3459-3459/m.example.so55711282dictionary D/DBPATH: DB Path is /data/data/m.example.so55711282dictionary/databases/dictionary.db
04-17 19:35:16.661 3459-3459/m.example.so55711282dictionary D/COPYDATABASE: Initiated Copy of the database file dictionary.db from the assets folder.
04-17 19:35:16.661 3459-3459/m.example.so55711282dictionary D/COPYDATABASE: Asset file dictionary.db found so attmepting to copy to /data/data/m.example.so55711282dictionary/databases/dictionary.db
04-17 19:35:16.662 3459-3459/m.example.so55711282dictionary D/COPYDATABASE: Attempting copy of block 1 which has 4096 bytes.
04-17 19:35:16.662 3459-3459/m.example.so55711282dictionary D/COPYDATABASE: Attempting copy of block 2 which has 4096 bytes.
04-17 19:35:16.662 3459-3459/m.example.so55711282dictionary D/COPYDATABASE: Attempting copy of block 3 which has 4096 bytes.
04-17 19:35:16.662 3459-3459/m.example.so55711282dictionary D/COPYDATABASE: Finished copying Database dictionary.db from the assets folder, to /data/data/m.example.so55711282dictionary/databases/dictionary.db12288were copied, in 3 blocks of size 4096.
04-17 19:35:16.662 3459-3459/m.example.so55711282dictionary D/COPYDATABASE: All Streams have been flushed and closed.
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: >>>>> Dumping cursor android.database.sqlite.SQLiteCursor@16011e94
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: 0 {
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: id=1
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: word=Apple
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: definition=Thing that drops from an Apple Tree.
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: }
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: 1 {
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: id=2
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: word=Bucket
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: definition=Hand held container with carrying hanlde.
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: }
04-17 19:35:16.689 3459-3459/m.example.so55711282dictionary I/System.out: 2 {
04-17 19:35:16.690 3459-3459/m.example.so55711282dictionary I/System.out: id=3
04-17 19:35:16.690 3459-3459/m.example.so55711282dictionary I/System.out: word=Yelllow
04-17 19:35:16.690 3459-3459/m.example.so55711282dictionary I/System.out: definition=A colour.
04-17 19:35:16.690 3459-3459/m.example.so55711282dictionary I/System.out: }
04-17 19:35:16.690 3459-3459/m.example.so55711282dictionary I/System.out: 3 {
04-17 19:35:16.690 3459-3459/m.example.so55711282dictionary I/System.out: id=4
04-17 19:35:16.690 3459-3459/m.example.so55711282dictionary I/System.out: word=Zebra
04-17 19:35:16.690 3459-3459/m.example.so55711282dictionary I/System.out: definition=A balck and white, horse-like animal.
04-17 19:35:16.690 3459-3459/m.example.so55711282dictionary I/System.out: }
04-17 19:35:16.690 3459-3459/m.example.so55711282dictionary I/System.out: <<<<<
Run 4.
The App is rerun (doesn't recopy the database and dumps the 4 rows)
Run 5.
The App is uninstalled and rerun (reflecting a new installation of the App when the Database version is at 2 (e.g. new download/install of the App from playstore)) :-
The Database (version with 4 rows) is copied and the 4 rows are dumped.
- Note that the The Database Version (as per the database file) is -666666666 message is included. This is shown when there is no database to be replaced (the number could easily be changed to suit).
来源：https://stackoverflow.com/questions/55711282/on-upgrade-method-not-getting-called-in-android-sqlite