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Кои методи могат да се използват за управление на различни версии на вече съществуващи бази данни?

Накратко един от начините би бил да копирате новия файл с активи на подходящото място, като същевременно запазите копие на оригиналния файл на базата данни, след което можете да приложите актуализациите, за да запазите ефективно данните на потребителя в новокопираната база данни. НО само ако приложението се надгражда за тази конкретна промяна и ако базата данни съществува.

Ако базата данни не съществува, трябва да се направи стандартното копие на файла с активи.

Ето пример как може да се направи това.

Този пример разчита в голяма степен на рутинни процедури, които позволяват управление и известно разпитване на файла в папката с активи и/или на самия файл на базата данни.

Клас, а именно DBAssetHandler.java се грижи за горното (както и за възможност за извличане на user_version AKA версията на базата данни при използване на SQLiteOpenHelper).

  • Обърнете внимание, че класът също е тестван и следователно се грижи за Android Pie и по този начин записване с предварителна запис (WAL по подразбиране в Pie), както и режим на дневник, предишният режим по подразбиране.

  • Също така имайте предвид, че ако използвате WAL, тогава трябва да се уверите, че базата данни е изцяло с контролни точки, вижте - Регистриране с предварителна запис

това е :-

public class DBAssetHandler {

    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) {

        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) {
            //String[] tempfiles = new String[]{"-journal","-wal","-shm"};
            //String backup = "-backup";
            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.");
        } 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) {
        copyDataBase(context, dbname,dbname,deleteExistingDB);
    }

    /**
     * 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();
            }
        }
    }
}
  • Надяваме се имената и коментарите на методите да обясняват горния код.

Файловете с активи са два :-

  • pev1.db - оригиналната съществуваща база данни, както е описано по-горе
  • pev1mod.db - модифицираното (допълнителна колона, ограничение UNIQUE и допълнителен ред).

Помощникът за база данни (подклас на SQLOpenHelper), а именно PEV2DBHelper.java , Трябва да се отбележи, че версията на базата данни (DBVERSION ) се използва за управление и като такъв е различен от версията на APK (която може да се променя по-често от DB)

  • Бяха открити проблеми при опит за използване на onUpgrade метод, следователно алтернативен подход, този за получаване на user_version на базите данни от файла, а не чрез SQLiteDatabase.

Ето PEV2DBHelper.java :-

/**
 * MORE COMPLEX EXAMPLE RETAINING USER DATA
 */
public class PEV2DBHelper extends SQLiteOpenHelper {

    public static final String DBNAME = "pev1.db";
    public static final String ASSETTOCOPY_DBV2 = "pev1mod.db"; //<<<<<<<<<< changed DB
    public static final int DBVERSION = 2; //<<<<<<<<<< increase and db file from assets will copied keeping existing data
    Context mContext;

    public PEV2DBHelper(Context context) {
        super(context, DBNAME, null, DBVERSION);


        int dbversion = DBAssetHandler.getVersionFromDBFile(context,DBNAME);
        Log.d("DBFILEVERSION","Database File Version = " + String.valueOf(dbversion));
        int af1version = DBAssetHandler.getVersionFromDBInAssetFolder(context,DBNAME);
        Log.d("DBFILEVERSION","Asset Database File Version = " + String.valueOf(af1version));
        int af2version = DBAssetHandler.getVersionFromDBInAssetFolder(context,ASSETTOCOPY_DBV2);
        Log.d("DBFILEVERSION","Asset Database File Version = " + String.valueOf(af2version));

        // cater for different DBVERSIONS (for testing )
        if (!DBAssetHandler.checkDataBase(context,DBNAME)) {

            //If new installation of the APP then copy the appropriate asset file for the DB
            switch (DBVERSION) {
                case 1:
                    DBAssetHandler.copyDataBase(context,DBNAME,DBNAME,false);
                    break;
                case 2:
                    DBAssetHandler.copyDataBase(context,DBNAME,ASSETTOCOPY_DBV2,false);
                    break;
            }
        }

        // If DBVERSION upgraded to 2 with modified DB but wanting to preserve used data
        if (DBAssetHandler.checkDataBase(context,DBNAME) & (DBVERSION > DBAssetHandler.getVersionFromDBFile(context, DBNAME)) & (DBVERSION == 2) ) {

            String[] oldcolumns = new String[]{"user","password"};

            // Copy in the new DB noting that delete option renames old (truue flag important)
            DBAssetHandler.copyDataBase(context,DBNAME,ASSETTOCOPY_DBV2,true);

            //Get the newly copied database
            SQLiteDatabase newdb = SQLiteDatabase.openDatabase(context.getDatabasePath(DBNAME).toString(),null,SQLiteDatabase.OPEN_READWRITE);
            //Get the old database (backup copy)
            SQLiteDatabase olddb =  SQLiteDatabase.openDatabase(context.getDatabasePath(DBNAME + DBAssetHandler.backup).toString(),null,SQLiteDatabase.OPEN_READWRITE);

            //Prepare to insert old rows (note user column is UNIQUE so pretty simple scenario just try inserting all and duplicates will be rejected)
            ContentValues cv = new ContentValues();
            Cursor oldcsr = olddb.query("user",null,null,null,null,null,null);
            newdb.beginTransaction();
            while (oldcsr.moveToNext()) {
                cv.clear();
                for (String columnname: oldcolumns) {
                    cv.put(columnname,oldcsr.getString(oldcsr.getColumnIndex(columnname)));
                }
                newdb.insert("user",null,cv);
            }
            newdb.setTransactionSuccessful();
            newdb.endTransaction();
            newdb.close();
            olddb.close();

            // Finally delete the renamed old database
            DBAssetHandler.clearForceBackups(context,DBNAME);
        }
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}
  • Обърнете внимание, че методите за добавяне и изтриване на извличане на редове са малко надути. Въпреки това, той е малко прекалено сложен, тъй като се справя с превключването между версиите, за да улесни демонстрацията.

Накрая е примерна дейност, която извиква използва PEV2DBHelper, записвайки схемата и редовете от таблицата в дневника.

Използваната дейност е MainActivity.java и е :-

public class MainActivity extends AppCompatActivity {

    PEV2DBHelper mDBHlpr2; //DBHelper for example that retains user data

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        doPEV2(); // Test simple more complex scenario
    }


    private void doPEV2() {

        mDBHlpr2 = new PEV2DBHelper(this);
        SQLiteDatabase db = mDBHlpr2.getWritableDatabase();
        Cursor csr = db.query("sqlite_master",null,null,null,null,null,null);
        DatabaseUtils.dumpCursor(csr);
        csr = db.query("user",null,null,null,null,null,null);
        DatabaseUtils.dumpCursor(csr);
        if (PEV2DBHelper.DBVERSION == 1) {
            addUserData(db);
            csr = db.query("user",null,null,null,null,null,null);
            DatabaseUtils.dumpCursor(csr);
        }
        csr.close();
        db.close();
    }

    /**
     * Add some user data for testing presevation of that data
     * @param db    the SQLitedatabase
     */
    private void addUserData(SQLiteDatabase db) {
        ContentValues cv = new ContentValues();
        cv.put("user","mr new user");
        cv.put("password","a password");
        db.insert("user",null,cv);
    }
}

Резултати

1. Когато стартирате за първи път с DBVERSION като 1 (чисто ново приложение)

В този случай файлът с активи pev1.db се копира от папката с активи, изходът е :-

2019-02-22 19:07:54.676 28670-28670/? D/DBFILEVERSION: Database File Version = -666666666
2019-02-22 19:07:54.677 28670-28670/? D/DBFILEVERSION: Asset Database File Version = 0
2019-02-22 19:07:54.677 28670-28670/? D/DBFILEVERSION: Asset Database File Version = 0
2019-02-22 19:07:54.677 28670-28670/? D/DBPATH: DB Path is /data/user/0/mjt.so54807516/databases/pev1.db
2019-02-22 19:07:54.677 28670-28670/? D/COPYDATABASE: Initiated Copy of the database file pev1.db from the assets folder.
2019-02-22 19:07:54.677 28670-28670/? D/COPYDATABASE: Asset file pev1.db found so attmepting to copy to /data/user/0/mjt.so54807516/databases/pev1.db
2019-02-22 19:07:54.677 28670-28670/? D/COPYDATABASE: Attempting copy of block 1 which has 4096 bytes.
2019-02-22 19:07:54.677 28670-28670/? D/COPYDATABASE: Attempting copy of block 2 which has 4096 bytes.
2019-02-22 19:07:54.677 28670-28670/? D/COPYDATABASE: Finished copying Database pev1.db from the assets folder, to  /data/user/0/mjt.so54807516/databases/pev1.db8192were copied, in 2 blocks of size 4096.
2019-02-22 19:07:54.678 28670-28670/? D/COPYDATABASE: All Streams have been flushed and closed.
2019-02-22 19:07:54.678 28670-28670/? D/DBPATH: DB Path is /data/user/0/mjt.so54807516/databases/pev1.db
2019-02-22 19:07:54.701 28670-28670/? I/System.out: >>>>> Dumping cursor [email protected]
2019-02-22 19:07:54.701 28670-28670/? I/System.out: 0 {
2019-02-22 19:07:54.701 28670-28670/? I/System.out:    type=table
2019-02-22 19:07:54.701 28670-28670/? I/System.out:    name=user
2019-02-22 19:07:54.701 28670-28670/? I/System.out:    tbl_name=user
2019-02-22 19:07:54.702 28670-28670/? I/System.out:    rootpage=2
2019-02-22 19:07:54.702 28670-28670/? I/System.out:    sql=CREATE TABLE "user" (
2019-02-22 19:07:54.702 28670-28670/? I/System.out:   "_id" INTEGER NOT NULL,
2019-02-22 19:07:54.702 28670-28670/? I/System.out:   "user" TEXT,
2019-02-22 19:07:54.702 28670-28670/? I/System.out:   "password" TEXT,
2019-02-22 19:07:54.702 28670-28670/? I/System.out:   PRIMARY KEY ("_id")
2019-02-22 19:07:54.702 28670-28670/? I/System.out: )
2019-02-22 19:07:54.702 28670-28670/? I/System.out: }
2019-02-22 19:07:54.702 28670-28670/? I/System.out: 1 {
2019-02-22 19:07:54.702 28670-28670/? I/System.out:    type=table
2019-02-22 19:07:54.702 28670-28670/? I/System.out:    name=android_metadata
2019-02-22 19:07:54.702 28670-28670/? I/System.out:    tbl_name=android_metadata
2019-02-22 19:07:54.702 28670-28670/? I/System.out:    rootpage=3
2019-02-22 19:07:54.702 28670-28670/? I/System.out:    sql=CREATE TABLE android_metadata (locale TEXT)
2019-02-22 19:07:54.702 28670-28670/? I/System.out: }
2019-02-22 19:07:54.702 28670-28670/? I/System.out: <<<<<
2019-02-22 19:07:54.703 28670-28670/? I/System.out: >>>>> Dumping cursor [email protected]
2019-02-22 19:07:54.703 28670-28670/? I/System.out: 0 {
2019-02-22 19:07:54.703 28670-28670/? I/System.out:    _id=1
2019-02-22 19:07:54.703 28670-28670/? I/System.out:    user=Fred
2019-02-22 19:07:54.703 28670-28670/? I/System.out:    password=fredpassword
2019-02-22 19:07:54.703 28670-28670/? I/System.out: }
2019-02-22 19:07:54.703 28670-28670/? I/System.out: 1 {
2019-02-22 19:07:54.703 28670-28670/? I/System.out:    _id=2
2019-02-22 19:07:54.703 28670-28670/? I/System.out:    user=Mary
2019-02-22 19:07:54.704 28670-28670/? I/System.out:    password=marypassword
2019-02-22 19:07:54.704 28670-28670/? I/System.out: }
2019-02-22 19:07:54.704 28670-28670/? I/System.out: <<<<<
2019-02-22 19:07:54.705 28670-28670/? I/System.out: >>>>> Dumping cursor [email protected]
2019-02-22 19:07:54.705 28670-28670/? I/System.out: 0 {
2019-02-22 19:07:54.705 28670-28670/? I/System.out:    _id=1
2019-02-22 19:07:54.705 28670-28670/? I/System.out:    user=Fred
2019-02-22 19:07:54.705 28670-28670/? I/System.out:    password=fredpassword
2019-02-22 19:07:54.706 28670-28670/? I/System.out: }
2019-02-22 19:07:54.706 28670-28670/? I/System.out: 1 {
2019-02-22 19:07:54.706 28670-28670/? I/System.out:    _id=2
2019-02-22 19:07:54.706 28670-28670/? I/System.out:    user=Mary
2019-02-22 19:07:54.706 28670-28670/? I/System.out:    password=marypassword
2019-02-22 19:07:54.706 28670-28670/? I/System.out: }
2019-02-22 19:07:54.706 28670-28670/? I/System.out: 2 {
2019-02-22 19:07:54.706 28670-28670/? I/System.out:    _id=3
2019-02-22 19:07:54.706 28670-28670/? I/System.out:    user=mr new user
2019-02-22 19:07:54.706 28670-28670/? I/System.out:    password=a password
2019-02-22 19:07:54.706 28670-28670/? I/System.out: }
2019-02-22 19:07:54.706 28670-28670/? I/System.out: <<<<<
  • -666666666 е версията, тъй като не е съществувал файл, следователно опитът да се получи версията от файла върна стойността по подразбиране, за да покаже, че версията не може да бъде получена.

2. Второ стартиране е същото, ОСВЕН номерът на версията е 1.

2019-02-22 19:09:43.724 28730-28730/mjt.so54807516 D/DBFILEVERSION: Database File Version = 1
2019-02-22 19:09:43.724 28730-28730/mjt.so54807516 D/DBFILEVERSION: Asset Database File Version = 0
2019-02-22 19:09:43.724 28730-28730/mjt.so54807516 D/DBFILEVERSION: Asset Database File Version = 0
2019-02-22 19:09:43.725 28730-28730/mjt.so54807516 D/DBPATH: DB Path is /data/user/0/mjt.so54807516/databases/pev1.db
2019-02-22 19:09:43.725 28730-28730/mjt.so54807516 D/DBPATH: DB Path is /data/user/0/mjt.so54807516/databases/pev1.db
2019-02-22 19:09:43.729 28730-28730/mjt.so54807516 I/System.out: >>>>> 
..... etc

3. Следващо стартиране след промяна на DBVERSION на 2

2019-02-22 19:13:49.157 28866-28866/mjt.so54807516 D/DBFILEVERSION: Database File Version = 1
2019-02-22 19:13:49.158 28866-28866/mjt.so54807516 D/DBFILEVERSION: Asset Database File Version = 0
2019-02-22 19:13:49.158 28866-28866/mjt.so54807516 D/DBFILEVERSION: Asset Database File Version = 0
2019-02-22 19:13:49.158 28866-28866/mjt.so54807516 D/DBPATH: DB Path is /data/user/0/mjt.so54807516/databases/pev1.db
2019-02-22 19:13:49.158 28866-28866/mjt.so54807516 D/DBPATH: DB Path is /data/user/0/mjt.so54807516/databases/pev1.db
2019-02-22 19:13:49.158 28866-28866/mjt.so54807516 D/COPYDATABASE: Initiated Copy of the database file pev1mod.db from the assets folder.
2019-02-22 19:13:49.159 28866-28866/mjt.so54807516 D/COPYDATABASE: Asset file pev1mod.db found so attmepting to copy to /data/user/0/mjt.so54807516/databases/pev1.db
2019-02-22 19:13:49.159 28866-28866/mjt.so54807516 D/COPYDATABASE: Attempting copy of block 1 which has 4096 bytes.
2019-02-22 19:13:49.159 28866-28866/mjt.so54807516 D/COPYDATABASE: Attempting copy of block 2 which has 4096 bytes.
2019-02-22 19:13:49.159 28866-28866/mjt.so54807516 D/COPYDATABASE: Attempting copy of block 3 which has 4096 bytes.
2019-02-22 19:13:49.159 28866-28866/mjt.so54807516 D/COPYDATABASE: Attempting copy of block 4 which has 4096 bytes.
2019-02-22 19:13:49.159 28866-28866/mjt.so54807516 D/COPYDATABASE: Finished copying Database pev1.db from the assets folder, to  /data/user/0/mjt.so54807516/databases/pev1.db16384were copied, in 4 blocks of size 4096.
2019-02-22 19:13:49.159 28866-28866/mjt.so54807516 D/COPYDATABASE: All Streams have been flushed and closed.
2019-02-22 19:13:49.186 28866-28866/mjt.so54807516 E/SQLiteDatabase: Error inserting password=fredpassword user=Fred
    android.database.sqlite.SQLiteConstraintException: UNIQUE constraint failed: user.user (code 2067 SQLITE_CONSTRAINT_UNIQUE)
        at 
    .........
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
2019-02-22 19:13:49.191 28866-28866/mjt.so54807516 E/SQLiteDatabase: Error inserting password=a password user=mr new user
    android.database.sqlite.SQLiteConstraintException: UNIQUE constraint failed: user.user (code 2067 SQLITE_CONSTRAINT_UNIQUE)
        at 
   .............
2019-02-22 19:13:49.209 28866-28866/mjt.so54807516 I/System.out: >>>>> Dumping cursor [email protected]
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out: 0 {
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:    type=table
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:    name=user
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:    tbl_name=user
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:    rootpage=2
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:    sql=CREATE TABLE "user" (
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:   "_id" INTEGER NOT NULL,
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:   "user" TEXT,
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:   "password" TEXT,
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:   "email" TEXT,
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:   PRIMARY KEY ("_id"),
2019-02-22 19:13:49.210 28866-28866/mjt.so54807516 I/System.out:   CONSTRAINT "user" UNIQUE ("user")
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out: )
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out: }
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out: 1 {
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out:    type=index
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out:    name=sqlite_autoindex_user_1
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out:    tbl_name=user
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out:    rootpage=4
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out:    sql=null
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out: }
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out: 2 {
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out:    type=table
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out:    name=android_metadata
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out:    tbl_name=android_metadata
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out:    rootpage=3
2019-02-22 19:13:49.211 28866-28866/mjt.so54807516 I/System.out:    sql=CREATE TABLE android_metadata (locale TEXT)
2019-02-22 19:13:49.212 28866-28866/mjt.so54807516 I/System.out: }
2019-02-22 19:13:49.212 28866-28866/mjt.so54807516 I/System.out: <<<<<
2019-02-22 19:13:49.212 28866-28866/mjt.so54807516 I/System.out: >>>>> Dumping cursor [email protected]
2019-02-22 19:13:49.213 28866-28866/mjt.so54807516 I/System.out: 0 {
2019-02-22 19:13:49.213 28866-28866/mjt.so54807516 I/System.out:    _id=1
2019-02-22 19:13:49.213 28866-28866/mjt.so54807516 I/System.out:    user=Fred
2019-02-22 19:13:49.213 28866-28866/mjt.so54807516 I/System.out:    password=fredpassword
2019-02-22 19:13:49.213 28866-28866/mjt.so54807516 I/System.out:    [email protected]
2019-02-22 19:13:49.213 28866-28866/mjt.so54807516 I/System.out: }
2019-02-22 19:13:49.213 28866-28866/mjt.so54807516 I/System.out: 1 {
2019-02-22 19:13:49.213 28866-28866/mjt.so54807516 I/System.out:    _id=2
2019-02-22 19:13:49.213 28866-28866/mjt.so54807516 I/System.out:    
...... etc


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  1. SQLite COUNT

  2. Как да стартирате SQLite заявка асинхронно във фонова нишка?

  3. Как работи SQLite Max().

  4. Таблицата не се създава sqlite android

  5. Как работи SQLite Lower().