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Method exceeds compiler instruction limit

Before I wrote this question, i've searched in all proposed answers, "stackoverflow" shows me but nothing fit my case.
My problem:
I wrote Room migration to copy old data from a table and add it to another table, and i need to specify all the columns in the query. I have something like 130 columns.
database.execSQL("INSERT INTO newTable(col1, ..n) SELECT col1, .... coln FROM oldTable")
When i executed my migration, i got this error:
method exceeds compiler instruction limit: 16602 in androidx.room.RoomOpenHelper$ValidationResult
Thx for your helps.

Running a test using 150 columns (151 including the id column) and thus :-
2022-05-11 06:29:50.050 16308-16308/a.a.so72188145javaroommaxcolumns D/INSERTSQL: INSERT INTO newtable (id,col1,col2,col3,col4,col5,col6,col7,col8,col9,col10,col11,col12,col13,col14,col15,col16,col17,col18,col19,col20,col21,col22,col23,col24,col25,col26,col27,col28,col29,col30,col31,col32,col33,col34,col35,col36,col37,col38,col39,col40,col41,col42,col43,col44,col45,col46,col47,col48,col49,col50,col51,col52,col53,col54,col55,col56,col57,col58,col59,col60,col61,col62,col63,col64,col65,col66,col67,col68,col69,col70,col71,col72,col73,col74,col75,col76,col77,col78,col79,col80,col81,col82,col83,col84,col85,col86,col87,col88,col89,col90,col91,col92,col93,col94,col95,col96,col97,col98,col99,col100,col101,col102,col103,col104,col105,col106,col107,col108,col109,col110,col111,col112,col113,col114,col115,col116,col117,col118,col119,col120,col121,col122,col123,col124,col125,col126,col127,col128,col129,col130,col131,col132,col133,col134,col135,col136,col137,col138,col139,col140,col141,col142,col143,col144,col145,col146,col147,col148,col149,col150) SELECT id,col1,col2,col3,col4,col5,col6,col7,col8,col9,col10,col11,col12,col13,col14,col15,col16,col17,col18,col19,col20,col21,col22,col23,col24,col25,col26,col27,col28,col29,col30,col31,col32,col33,col34,col35,col36,col37,col38,col39,col40,col41,col42,col43,col44,col45,col46,col47,col48,col49,col50,col51,col52,col53,col54,col55,col56,col57,col58,col59,col60,col61,col62,col63,col64,col65,col66,col67,col68,col69,col70,col71,col72,col73,col74,col75,col76,col77,col78,col79,col80,col81,col82,col83,col84,col85,col86,col87,col88,col89,col90,col91,col92,col93,col94,col95,col96,col97,col98,col99,col100,col101,col102,col103,col104,col105,col106,col107,col108,col109,col110,col111,col112,col113,col114,col115,col116,col117,col118,col119,col120,col121,col122,col123,col124,col125,col126,col127,col128,col129,col130,col131,col132,col133,col134,col135,col136,col137,col138,col139,col140,col141,col142,col143,col144,col145,col146,col147,col148,col149,col150 FROM oldtable;
Worked fine (Room 2.5.0-aplha01 and Android 30 emulator). I suspect that the issue may not be the number of columns but elsewhere in the SQL.
The above SQL was extracted from the log, it was output to the log exactly as was then used (see testing code below).
A work-around IF you have columns that can be null and a sufficient number of them to circumvent the issue. Have an INSERT that inserts a manageable number of columns allowing the other columns to default to null, followed by 1 or more UPDATEs to apply the subsequent values to override the nulls.
Another work-around could be to extract all columns SELECT * .... into a Cursor and then build a ContentValues from the Cursor (on a per row basis) and use the SupportSQliteDatabase's insert method. Something along the lines of:-
Cursor csr = database.query("SELECT * FROM oldtable");
database.beginTransaction();
ContentValues cv = new ContentValues();
while (csr.moveToNext()) {
cv.clear();
for (int i=0; i < csr.getColumnCount(); i++) {
if (!csr.getColumnName(i).equals("col133")) { //<<<<< skip col133 as an example
cv.put(csr.getColumnName(i),csr.getString(i));
}
}
database.insert("newTable", SQLiteDatabase.CONFLICT_IGNORE,cv);
}
database.setTransactionSuccessful();
database.endTransaction();
Full code used for testing
Note that the only change between the 2 is the version number. So initially the code is run (after uninstalling the App) with version 1 (so no Migration). To test it's just a matter, of then changing the version to 2.
The #Entity annotated class OldTable:-
#Entity
class OldTable {
#PrimaryKey
Long id=null;
String col1;
String col2;
String col3;
.... (i.e. all missing numbers)
String col147;
String col148;
String col149;
String col150;
}
The #Dao annotated interface (not actually used) AllDao
#Dao
interface AllDao {
#Insert(onConflict = OnConflictStrategy.IGNORE)
long insert(OldTable oldTable);
}
The #Database annotated class TheDatabase :-
#Database(entities = {OldTable.class},version = MainActivity.DATABASE_VERSION,exportSchema = false)
abstract class TheDatabase extends RoomDatabase {
abstract AllDao getAllDao();
private static volatile TheDatabase INSTANCE = null;
static TheDatabase getINSTANCE(Context context) {
if (INSTANCE == null) {
INSTANCE = Room.databaseBuilder(context,TheDatabase.class,MainActivity.DATABASE_NAME)
.allowMainThreadQueries()
.addMigrations(MIGRATION_1_2)
.build();
}
return INSTANCE;
}
static Migration MIGRATION_1_2 = new Migration(1,2) {
#Override
public void migrate(#NonNull SupportSQLiteDatabase database) {
StringBuilder sb = new StringBuilder();
StringBuilder sb2 = new StringBuilder();
ArrayList<String> columns = new ArrayList<>();
for (int i=0; i < MainActivity.column_count;i++) {
columns.add("col" + (i+1));
if (i>0) {
sb.append(",");
sb2.append(",");
}
sb.append(columns.get(i));
sb2.append(columns.get(i)).append(" TEXT");
}
String columnsAsCSV = sb.toString();
String columnDefs = sb2.toString();
database.execSQL("DROP TABLE IF EXISTS newtable");
database.execSQL("CREATE TABLE IF NOT EXISTS newtable (id INTEGER PRIMARY KEY," + columnDefs + ");");
String insertSQL = "INSERT INTO newtable (id,"+columnsAsCSV+") SELECT id,"+columnsAsCSV+" FROM oldtable;";
Log.d("INSERTSQL",insertSQL);
database.execSQL(insertSQL);
}
};
}
And finally putting it alltogether MainActivity :-
public class MainActivity extends AppCompatActivity {
public static final String DATABASE_NAME = "the_database.db";
public static final int DATABASE_VERSION = 2;
public static final int column_count = 150;
private ArrayList<String> column_names = new ArrayList<>();
private String allColumnsAsCSV = "";
TheDatabase db;
AllDao dao;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
BuildColumns();
db = TheDatabase.getINSTANCE(this);
dao = db.getAllDao();
SupportSQLiteDatabase supdb = db.getOpenHelper().getWritableDatabase();
StringBuilder sb = new StringBuilder();
for (int i=0;i < 100; i++) {
sb = new StringBuilder();
sb.append("INSERT INTO oldtable (").append(allColumnsAsCSV).append(") VALUES(");
for(int ii=0;ii<column_count;ii++) {
if (ii > 0) {
sb.append(",");
}
sb.append("'").append(column_names.get(ii)).append(i).append(ii).append("'");
}
sb.append(")");
supdb.execSQL(sb.toString());
}
}
void BuildColumns() {
column_names.clear();
allColumnsAsCSV = "";
StringBuilder sb = new StringBuilder();
for (int i=0; i < column_count; i++) {
column_names.add("col" + (i+1));
if (i>0) {
sb.append(",");
}
sb.append(column_names.get(i));
}
allColumnsAsCSV = sb.toString();
}
}

How to encrypt sqlite texts without 3rd party libraries (Android)

I'm using an external database inside my android application and it directly embeds inside the apk package after compiling.
As I want to implement in app purchase in order to access some of its data I don't want to leave it without any encryption.
I used Sqlcipher library but it makes the app too big and slow.
Isn't there any other way to do this? For example an algorithm to encrypt the strings so I put the encrypted text in database and decrypt it inside application code?

The following is an example App that Encrypts part of the data that can then be turned on. It is based upon the code in my comment.
Stage 1 - The Master Database.
To start with you need the database that is to be the basis of the encrypted database (i.e. the MASTER database that IS NOT include in the App, it's use is to create the Encrypted database (or databases, perhaps a library, each database with a unique password/secret key if you wanted greater security)) in part consider this (as is used throughout the example) :-
As you can see this one will work by having a table called FreeData and another called PaidData. The tables definitions are the same EXCEPT that for the PaidData there is no ID column (the intention of this method is to decrypt the rows in the PaidData into the FreeData when/if the requested and the SecretKey (password) is valid.).
So The FreeData table looks like :-
The PaidData table looks like :-
So the only difference between the tables is the actual data contained within and that the id column is missing.
The id's will be generated when the encrypted data is extracted from the PaidData table, decrypted and the inserted into the FreeData table. Thus just one decryption is required to get access to the data.
Stage 2 - Generating the Encrypted Database for distribution with the App
This is done by a App just for this purpose using the EncryptDecrypt class very similar to the one at Encrypt data in SQLite
as per EncryptDecrypt.java
class EncryptDecrypt {
private Cipher cipher;
private static SecretKeySpec secretKeySpec;
private static IvParameterSpec ivParameterSpec;
private boolean do_encrypt = true;
/**
* Construct EncryptDecrypt instance that does not check user login-in
* mode, thus the assumption is that this user is NOT the special user
* NOUSER that doesn't require a password to login; this constructor
* is designed to ONLY be used when a user has been added by NOUSER,
* and to then encrypt the data using the enccryptForced method solely
* to encrypt any existing card data for the new user that has a password.
*
* #param context The context, required for database usage (user)
* #param skey The secret key to be used to encrypt/decrypt
*/
EncryptDecrypt(Context context, String skey) {
//DBUsersMethods users = new DBUsersMethods(context);
String saltasString = "there is no dark side of the moon it is all dark.";
String paddedskey = (skey + saltasString).substring(0,16);
secretKeySpec = new SecretKeySpec(paddedskey.getBytes(),"AES/CBC/PKCS5Padding");
ivParameterSpec = new IvParameterSpec((saltasString.substring(0,16)).getBytes());
try {
cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
} catch (Exception e){
//e.printStackTrace();
}
}
/**
* Normal encryption routine that will not encrypt data if the user is
* the special case NOUSER (i.e LOGIN mode is NOUSER), otherwise data
* is encrypted.
*
* #Param toEncrypt The string to be encrypted
* #return The encryted (or not if NOUSER) data as a string
*/
String encrypt(String toEncrypt) {
if (!do_encrypt) {
return toEncrypt;
}
byte[] encrypted;
try {
cipher.init(Cipher.ENCRYPT_MODE,secretKeySpec,ivParameterSpec);
encrypted = cipher.doFinal(toEncrypt.getBytes());
} catch (Exception e) {
//e.printStackTrace();
return null;
}
return Base64.encodeToString(encrypted, Base64.DEFAULT);
}
/**
* Encryption, irrespective of the USER type, noting that this should
* only be used in conjunction with an EncryptDecrypt instance created
* using the 2nd/extended constructor
*
* #param toEncrypt The string to be encrypted
* #return The encrypted data as a string
*/
String encryptForced(String toEncrypt) {
byte[] encrypted;
try {
cipher.init(Cipher.ENCRYPT_MODE,secretKeySpec,ivParameterSpec);
encrypted = cipher.doFinal(toEncrypt.getBytes());
} catch (Exception e) {
//e.printStackTrace();
return null;
}
return Base64.encodeToString(encrypted,Base64.DEFAULT);
}
/**
* Decrypt an encrypted string
* #param toDecrypt The encrypted string to be decrypted
* #return The decrypted string
*/
String decrypt(String toDecrypt) {
if (!do_encrypt) {
return toDecrypt;
}
byte[] decrypted;
try {
cipher.init(Cipher.DECRYPT_MODE,secretKeySpec,ivParameterSpec);
decrypted = cipher.doFinal(Base64.decode(toDecrypt,Base64.DEFAULT));
} catch (Exception e) {
//e.printStackTrace();
return null;
}
return new String(decrypted);
}
}
As this was designed for user login and multiple users where a salt was part of the database the salt has been hard coded using :- String saltasString = "there is no dark side of the moon it is all dark.";, The phrase can be changed as long as it is at least 16 characters in length (only the first 16 bytes are used).
A class is used to cater for potential flexibility/expansion where multiple tables can be specified or not for encryption and for multiple columns that can be encrypted, copied asis or skipped (e.g. id's would probably be skipped (in the example it's not even defined as a column).).
This class is TableColumnConvertList.java and is :-
public class TableColumnConvertList {
private ArrayList<TableEntry> tables;
public TableColumnConvertList() {
this.tables = new ArrayList<>();
}
public String[] getTables() {
String[] tableList = new String[tables.size()];
int ix = 0;
for (TableEntry te: this.tables) {
tableList[ix++] = te.getSourceTableName();
}
return tableList;
}
public String[] getTableColumnNamesToEncrypt(String tableName) {
String[] rv = null;
for(TableEntry te: this.tables) {
if (te.getSourceTableName().equals(tableName)) {
rv = new String[te.getColumnNamesToEncrypt().size()];
int ix=0;
for (String s: te.getColumnNamesToEncrypt()) {
rv[ix++] = s;
}
}
}
return rv;
}
public String[] getTableColumnNamesToCopyAsis(String tableName) {
String[] rv = null;
for (TableEntry te: this.tables) {
if (te.getSourceTableName().equals(tableName)) {
rv = new String[te.getColumnNamesToCopyAsis().size()];
int ix=0;
for (String s: te.getColumnNamesToCopyAsis()) {
rv[ix++] = s;
}
}
}
return rv;
}
public String[] getTableColumnNamesToSkip(String tableName) {
String[] rv = null;
for (TableEntry te: this.tables) {
if (te.sourceTableName.equals(tableName)) {
rv = new String[te.getColumnNamesToSkip().size()];
int ix =0;
for (String s: te.getColumnNamesToSkip()) {
rv[ix++] = s;
}
}
}
return rv;
}
public void addTable(
String sourceTableName,
String destinationTableName,
String[] columnNamesToEncrypt,
String[] columnNamesToCopyAsis,
String[] columnNamesToSkip
) {
tables.add(
new TableEntry(
sourceTableName,
destinationTableName,
columnNamesToEncrypt,
columnNamesToCopyAsis,
columnNamesToSkip
)
);
}
private class TableEntry {
private String sourceTableName;
private String destinationTableName;
private ArrayList<String> columnNamesToEncrypt;
private ArrayList<String> columnNamesToCopyAsis;
private ArrayList<String> columnNamesToSkip;
private TableEntry() {}
private TableEntry(String sourceTableName,
String destinationTableName,
String[] columnNamesToEncrypt,
String[] columnNamesToCopyAsis,
String[] columnNamesToSkip
) {
this.sourceTableName = sourceTableName;
this.destinationTableName = destinationTableName;
this.columnNamesToEncrypt = new ArrayList<>();
if (columnNamesToEncrypt != null && columnNamesToEncrypt.length > 0) {
for (String s: columnNamesToEncrypt) {
addColumn(s);
}
}
}
private void addColumn(String s) {
this.columnNamesToEncrypt.add(s);
}
private String getSourceTableName() {
return sourceTableName;
}
public String getDestinationTableName() {
return destinationTableName;
}
public void setSourceTableName(String sourceTableName) {
this.sourceTableName = sourceTableName;
}
public void setDestinationTableName(String destinationTableName) {
this.destinationTableName = destinationTableName;
}
private ArrayList<String> getColumnNamesToEncrypt() {
return columnNamesToEncrypt;
}
public void setColumnNamesToEncrypt(ArrayList<String> columnNamesToEncrypt) {
this.columnNamesToEncrypt = columnNamesToEncrypt;
}
private ArrayList<String> getColumnNamesToCopyAsis() {
return columnNamesToCopyAsis;
}
public void setColumnNamesToCopyAsis(ArrayList<String> columnNamesToCopyAsis) {
this.columnNamesToCopyAsis = columnNamesToCopyAsis;
}
public ArrayList<String> getColumnNamesToSkip() {
return columnNamesToSkip;
}
public void setColumnNamesToSkip(ArrayList<String> columnNamesToSkip) {
this.columnNamesToSkip = columnNamesToSkip;
}
}
}
The rest of this basic App, at present, is all in a single activity that uses two input's (EditTexts) :-
The secret key used to encrypt
The database name (file name) of the encrypted database.
Code in the App prevents using the same name as the base database, which needs to be copied into the assets folder.
and a Button, to initiate the Encryption if the input is good (to a fashion aka with limited validation).
This the layout xml activiy_main.xml is :-
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="10dp"
tools:context=".MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Database EncryptTool" />
<EditText
android:id="#+id/secretkey"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:hint="Secret Key to use to Encrypt the Database."
>
</EditText>
<EditText
android:id="#+id/databasename"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="MyDatabase"
android:hint="Database Name"
>
</EditText>
<Button
android:id="#+id/encrypt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="ENCRYPT"
android:visibility="gone"
>
</Button>
</LinearLayout>
MainActivity.java where the work is done is :-
public class MainActivity extends AppCompatActivity {
public static final String ASSETDB_NAME = "basedb.db";
public static final int ASSETDB_NOT_FOUND = -10;
public static final int ASSETFILE_OPEN_ERROR = -11;
public static final int ASSETDB_OPEN_ERROR = -12;
public static final int ASSETDB_COPY_ERROR = -13;
public static final int ASSETDB_FLUSH_ERROR = -14;
public static final int ASSETDB_CLOSE_ERROR = -15;
public static final int ASSETFILE_CLOSE_ERROR = -16;
public static final int ASSETDB_CREATED_SUCCESSFULLY = 0;
public static final int BUFFERSIZE = 1024 * 4;
EditText mSecretKey, mDBName;
Button mEncryptButton;
TableColumnConvertList mTCCL = new TableColumnConvertList();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDBName = this.findViewById(R.id.databasename);
mSecretKey = this.findViewById(R.id.secretkey);
mEncryptButton = this.findViewById(R.id.encrypt);
//<<<<<<<<< set what data to encrypt i.e. table(s) and the column(s) in the table >>>>>>>>>
mTCCL.addTable(
"PaidData",
"FreeData",
new String[]{"theData"},
new String[]{},
new String[]{"id"}
);
if (getDBFromAsset() >= 0) {
mEncryptButton.setVisibility(View.VISIBLE);
mEncryptButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (mDBName.getText().toString().length() < 1) {
Toast.makeText(
v.getContext(),
"The Database Name cannot be blank.",
Toast.LENGTH_LONG
).show();
mDBName.requestFocus();
return;
}
if (mDBName.getText().toString().equals(ASSETDB_NAME)) {
Toast.makeText(
v.getContext(),
"Database Name cannot be "
+ ASSETDB_NAME
+ ". Please change the name.",
Toast.LENGTH_LONG
).show();
mDBName.requestFocus();
return;
}
if (mSecretKey.getText().toString().length() < 1) {
Toast.makeText(
v.getContext(),
"The Secret Key cannot be blank.",
Toast.LENGTH_LONG
).show();
mSecretKey.requestFocus();
return;
}
if (createEncryptedDatabase(mTCCL,
mDBName.getText().toString(),
mSecretKey.getText().toString()
) == 0) {
Toast.makeText(v.getContext(),"Successfully Encrypted Database " + mDBName + " using Secret Key " + mSecretKey,Toast.LENGTH_LONG).show();
}
}
});
}
}
private boolean checkIfDataBaseExists(String databaseName) {
File dbFile = new File(this.getDatabasePath(databaseName).getPath());
if (dbFile.exists()) {
return true;
} else {
if (!dbFile.getParentFile().exists()) {
dbFile.getParentFile().mkdirs();
}
}
return false;
}
private boolean checkIfAssetDBExists() {
try {
InputStream is = this.getAssets().open(ASSETDB_NAME);
is.close();
return true;
} catch (IOException e) {
return false;
}
}
private int getDBFromAsset() {
int rv = ASSETDB_NOT_FOUND;
File dbFile = new File(this.getDatabasePath(ASSETDB_NAME).getPath());
InputStream is;
FileOutputStream os;
int read_length;
byte[] buffer = new byte[BUFFERSIZE];
if (!checkIfAssetDBExists()) {
return ASSETDB_NOT_FOUND;
}
if (checkIfDataBaseExists(ASSETDB_NAME)) {
dbFile.delete();
}
try {
rv = ASSETFILE_OPEN_ERROR;
is = this.getAssets().open(ASSETDB_NAME);
rv = ASSETDB_OPEN_ERROR;
os = new FileOutputStream(dbFile);
rv = ASSETDB_COPY_ERROR;
while ((read_length = is.read(buffer)) > 0) {
os.write(buffer,0,read_length);
}
rv = ASSETDB_FLUSH_ERROR;
os.flush();
rv = ASSETDB_CLOSE_ERROR;
os.close();
rv = ASSETFILE_CLOSE_ERROR;
is.close();
rv = ASSETDB_CREATED_SUCCESSFULLY;
} catch (IOException e) {
e.printStackTrace();
}
return rv;
}
private int createEncryptedDatabase(TableColumnConvertList tableColumnConvertList, String databaseName, String key) {
File copiedAssetDB = new File(this.getDatabasePath(ASSETDB_NAME).getPath());
File encryptedDB = new File(this.getDatabasePath(databaseName).getPath());
if (encryptedDB.exists()) {
encryptedDB.delete();
}
try {
byte[] buffer = new byte[BUFFERSIZE];
int read_length;
InputStream is = new FileInputStream(copiedAssetDB);
OutputStream os = new FileOutputStream(encryptedDB);
while ((read_length = is.read(buffer)) > 0) {
os.write(buffer,0,read_length);
}
os.flush();
os.close();
is.close();
} catch (IOException e) {
e.printStackTrace();
return -1;
}
SQLiteDatabase db = SQLiteDatabase.openDatabase(encryptedDB.getPath(),null,SQLiteDatabase.OPEN_READWRITE);
EncryptDecrypt ed = new EncryptDecrypt(this,key);
int errorcount = 0;
db.beginTransaction();
for (String t: tableColumnConvertList.getTables()) {
ContentValues cv = new ContentValues();
String[] columnsToEncrypt = tableColumnConvertList.getTableColumnNamesToEncrypt(t);
String[] columnOriginalValues = new String[columnsToEncrypt.length];
Cursor c = db.query(true,t,columnsToEncrypt,null,null,null,null,null, null);
int totalRows = c.getCount();
int updatedRows = 0;
while (c.moveToNext()) {
cv.clear();
int ovix=0;
StringBuilder whereClause = new StringBuilder();
for (String s: c.getColumnNames()) {
for (String ec: columnsToEncrypt ) {
if (s.equals(ec)) {
cv.put(s,ed.encrypt(c.getString(c.getColumnIndex(s))));
columnOriginalValues[ovix++] = c.getString(c.getColumnIndex(s));
if (whereClause.length() > 0) {
whereClause.append(" AND ");
}
whereClause.append(s).append("=?");
}
}
}
updatedRows += db.update(t,cv,whereClause.toString(),columnOriginalValues);
}
c.close();
Log.d("ENCRYPTRESULT","Read " + totalRows + " DISTINCT ROWS. Updated " + updatedRows);
errorcount += totalRows - updatedRows;
}
if (errorcount == 0) {
db.setTransactionSuccessful();
} else {
Toast.makeText(
this,
"Errors encountered Encrypting Database. Rolled back (not changed)",
Toast.LENGTH_LONG
).show();
}
db.endTransaction();
return errorcount;
}
}
Of importance is this line/code :-
TableColumnConvertList mTCCL = new TableColumnConvertList();
..........
//<<<<<<<<< set what data to encrypt i.e. table(s) and the column(s) in the table >>>>>>>>>
mTCCL.addTable(
"PaidData",
"FreeData",
new String[]{"theData"},
new String[]{},
new String[]{"id"}
);
This adds a table to the List of tables to be encrypted. It's parameters are :-
The name of the table that is to be included in Encryption.
the name of the table into which the encrypted data is to be stored.
Note this functionality is not present but could be added. As such the value is ignored.
The list of columns that are to be encrypted.
The list of columns that are to be copied asis.
This functionality is not present but could be added. As such the list is ignored.
The list of columns that are to be skipped (e.g. id columns).
Although coded, the functionality is not present. As such the list is ignored.
What the App does.
The final result is an database as per the database in the assets folder (named basedb.db) that has the data in the theData column of the PaidData table encrypted, but the the FreeData table is unchanged. This database could then be copied (e.g. using device explorer) and then included as an asset in the App that is to be distributed. That App could include a reversal of the Encryption using the secret key and the decryption part of the EncryptDecrypt class.
e.g.
The FreeData table :-
The PaidData table :-
When the App is started if copies the database (hard coded as basedb.db) from the assets folder it it exists and makes the Encrypt button visible.
If the Encrypt button isn't visible then the asset file was not located. So it's time to correct the issue (provide the correct database file).
Note as this is just a demo many checks/options that could/should be done or added are skipped for brevity.
If the Encrypt button appears then encryption is just a matter of hitting the button.
After hitting the button createEncryptedDatabase method is called.
This creates a copy, this will be the encrypted database, of the database copied from the assets folder by copying the file to it's new name (as per the given database name which MUST be different to the asset's file name).
Using the copied database it queries the table(s) defined in mTCCL (an instance of the TableColumnConvertList class) .
The query will extract data only for the columns that have been specified as those to be encrypted. The query only obtain distinct rows (i.e if multiple rows exist that has the same data in the columns then only one of the rows is extracted).
For each extracted row :-
The commonly used ContentValues instance is cleared.
The whereClause StringBuilder is cleared.
Each column in the Cursor is checked to see if it is a column, defined in the table being processed (it should be as only column t be encrypted are extracted).
if not then it is skipped.
The original value is saved in the appropriate element of the string array columnOriginalValues (this to be used as the bind parameters for the WHERE clause of the UPDATE)
An element of the ContentValues instance is added with the current column name and the encrypted data.
This is done as per cv.put(s,ed.encrypt(c.getString(c.getColumnIndex(s))));
If the length of the whereClause is greater than 0 then AND is added to the whereClause, then the column name suffixed with =? is added to the whereClause being built.
After all columns have been processed the SQLiteDatabase update method is called to update the columns setting the values to the encrypted values WHERE all the column match the original data.
After all rows have been processed the Cursor is closed and the next table processed.
If after all tables have been processed then error count is 0 then the transaction is set as successful, otherwise a message is Toasted Errors encountered Encrypting Database. Rolled back (not changed).
The transaction is then ended (if not set as successful then the data is not updated but rolled back).
The database will be in the data/data/package_name/databases folder e.g. :-

Example Decryption App for Answer 1
Note that the database (MyDatabase) was copied from data/data/package_name/databases of the App from the previous answer (i.e. the encrypted database) into the assets folder of this app
The following is a very basic App that initially only has the Free Data, but as an Edit Text and a Button that allows the Paid Data to be decrypted and retrieved. The available data (Free Data initially) is listed in a ListView; after decryption the PaidData having been copied to the FreeData is then avialable and listed.
Notes
the data can be decrypted numerous times and each such successful attempt will add and display more rows.
EncryptDEcrypt.java is identical to the one used in the Encrypt tool.
The Database Helper is :-
public class DBHelper extends SQLiteOpenHelper {
public static final String DBNAME = "MyDatabase";
public static final int DBVERSION = 1;
public static final String TBL_FREEDATA = "FreeData";
public static final String COL_FREEDATA_ID = "id";
public static final String COL_THEDATA = "theData";
SQLiteDatabase mDB;
public DBHelper(Context context) {
super(context, DBNAME, null, DBVERSION);
loadDBFromAssets(context);
mDB = this.getWritableDatabase();
}
#Override
public void onCreate(SQLiteDatabase db) {
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
public long insertFreeDataRow(String theData) {
ContentValues cv = new ContentValues();
cv.put(COL_THEDATA,theData);
return mDB.insert(TBL_FREEDATA,null,cv);
}
public Cursor getAllAvialableData() {
return mDB.query(TBL_FREEDATA,new
String[]{"*",COL_FREEDATA_ID + " AS " + BaseColumns._ID},
null,null,null,null,null
);
}
public void decryptAndLoadPaidData(Context context, String secretKey) {
EncryptDecrypt ed = new EncryptDecrypt(context,secretKey);
mDB.beginTransaction();
Cursor c = mDB.query("PaidData",null,null,null,null,null,null);
while (c.moveToNext()) {
String decrypted_data = ed.decrypt(c.getString(c.getColumnIndex(COL_THEDATA)));
if (decrypted_data != null) {
insertFreeDataRow(decrypted_data);
} else {
Toast.makeText(context,"Naughty, that's not the password.",Toast.LENGTH_LONG).show();
}
}
c.close();
mDB.setTransactionSuccessful();
mDB.endTransaction();
}
private boolean loadDBFromAssets(Context context) {
File dbFile = new File(context.getDatabasePath(DBNAME).getPath());
byte[] buffer = new byte[1024 * 4];
int read_length = 0;
if (dbFile.exists()) return true;
if (!dbFile.getParentFile().exists()) {
dbFile.getParentFile().mkdirs();
}
try {
InputStream assetdb = context.getAssets().open(DBNAME);
OutputStream realdb = new FileOutputStream(dbFile);
while ((read_length = assetdb.read(buffer)) > 0) {
realdb.write(buffer,0,read_length);
}
realdb.flush();
realdb.close();
assetdb.close();
} catch (IOException e) {
e.printStackTrace();
return false;
}
return true;
}
}
MainActivity.java is :-
public class MainActivity extends AppCompatActivity {
ListView mListView;
EditText mSecretKeyInput;
Button mDecrypt;
SimpleCursorAdapter mSCA;
Cursor mAllTheData;
DBHelper mDBhlpr;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mListView = this.findViewById(R.id.list);
mSecretKeyInput = this.findViewById(R.id.secretKey);
mDecrypt = this.findViewById(R.id.decrypt);
mDBhlpr = new DBHelper(this);
manageListView();
manageDecryptButton();
}
private void manageListView() {
mAllTheData = mDBhlpr.getAllAvialableData();
if (mSCA == null) {
mSCA = new SimpleCursorAdapter(
this,android.R.layout.simple_list_item_1,mAllTheData,new String[]{DBHelper.COL_THEDATA},new int[]{android.R.id.text1},0);
mListView.setAdapter(mSCA);
} else {
mSCA.swapCursor(mAllTheData);
}
}
private void manageDecryptButton() {
mDecrypt.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (mSecretKeyInput.getText().toString().length() > 0) {
mDBhlpr.decryptAndLoadPaidData(v.getContext(),mSecretKeyInput.getText().toString());
manageListView();
}
}
});
}
}
Result
When first run the App only shows the Free Data as per :-
If the correct password/secret key is input and the Get Paid Data button is pressed then the extra data is added :-
If an incorrect password is provided, then the data is not loaded and a toast appears indicating the wrong password.

Database copied to local file system and Room Query won't work

I am trying to query data with Androids persistence library Room from a existing Database. No compilation error or runtime error. There is just no result in the cursor.
The query is checked and looks fine (also in the generated Java as mentioned in the answer of 'Pinakin' Android Room Database DAO debug log
The database existis in the /data/data/com.project/databases/ folder.
The database has the correct size but there are no other files such as mentioned in the answer of 'kosas' Android Room database file is empty
Similar style of copying as shown here https://android.jlelse.eu/room-persistence-library-with-pre-populated-database-5f17ef103d3d. I only changed the constructor to:
grammarDatabase = GrammarDatabase.getInstance(appContext);
because my GrammarDatabase looks like this:
#Database(
entities = {
Term.class
}, version = 1, exportSchema = false
)
public abstract class GrammarDatabase extends RoomDatabase {
private static final String DB_NAME = "database.db";
private static volatile GrammarDatabase instance;
public static synchronized GrammarDatabase getInstance(Context context) {
if (instance == null) {
instance = create(context);
}
return instance;
}
private static GrammarDatabase create(final Context context) {
return Room.databaseBuilder(context, GrammarDatabase.class, DB_NAME).fallbackToDestructiveMigration().allowMainThreadQueries().build();
}
public abstract TermDao getTermDao();
}
The .fallbackToDestructiveMigration() and .allowMainThreadQueries is just for testing purposes.
The interface 'TermDao_Impl' (query string shortened):
#Override
public Cursor getSearchContent(String searchTerm, String languageCode) {
final String _sql = "SELECT T._id, T.term FROM term AS T INNER JOIN ... INNER JOIN language AS L INNER JOIN ... AND L.code= ? AND T.term LIKE ?";
final RoomSQLiteQuery _statement = RoomSQLiteQuery.acquire(_sql, 2);
int _argIndex = 1;
if (languageCode == null) {
_statement.bindNull(_argIndex);
} else {
_statement.bindString(_argIndex, languageCode);
}
_argIndex = 2;
if (searchTerm == null) {
_statement.bindNull(_argIndex);
} else {
_statement.bindString(_argIndex, searchTerm);
}
final Cursor _tmpResult = __db.query(_statement);
return _tmpResult;
}
Call in MainActivity:
First: database = DatabaseHelper.getInstance(context).getGrammarDatabase();
Then:
Cursor c = database.getTermDao().getSearchContent("'"+searchTerm+"'", "'"+currentLanguageCode+"'");
if (c.moveToNext()) {
System.out.println("Found!");
System.out.println(c.getString(c.getColumnIndex("T.term")));
}
Tried to call with " ' " around the arguments and without.
So the cursor is empty eventhough the query will have a result (tested in DB Browser for SQLite). "Found!" Is not printed.

Suggestions to improve SQLite perfromance

I am saving data to an SQLite Database. It's taking a while for small amounts of data to be saved. I'm using: beginTransaction();
setTransactionSuccessful();, endTransaction(); etc but it doesn't improve performance. I'm considering switching to RealmDB if I can't improve this. Does anyone have any tips? Cheers
public enum DbSingleton {
INSTANCE;
private DatabaseHandler db;
public Context context;
private DatabaseHandler getDatabaseHandler(Context context) {
if (db != null) {
return db;
} else {
if (MainActivity.mainActivity == null) {
SQLiteDatabase.loadLibs(context);
return db = new DatabaseHandler(context); //make static context field in area this is used. e.g. main
} else {
return db = new DatabaseHandler(MainActivity.mainActivity);
}
}
}
//will provide one sample for reference now
public void insert(Context context, String table, ContentValues values) {
SQLiteDatabase.loadLibs(MainActivity.mainActivity);
//note this line
SQLiteDatabase sql = getDatabaseHandler(context).getWritableDatabase(DatabaseHandler.DB_PASSWD);
try {
sql.beginTransaction();
sql.insert(table, null, values);
// Log.i("Values being sent to db", values.toString());
sql.setTransactionSuccessful();
sql.endTransaction();
} catch (SQLiteException ex) {
Log.e("SQL EXCEPTION", ex.toString());
} finally {
sql.close();
}
}
public Cursor select(Context context, String statement, String[] selectArgs) {
SQLiteDatabase sql = getDatabaseHandler(context).getReadableDatabase(DatabaseHandler.DB_PASSWD);
if (selectArgs == null) {
return sql.rawQuery(statement, null);
} else {
return sql.rawQuery(statement, selectArgs);
}
}
public int Update(Context context, String table, ContentValues values, String where, String[] whereArgs) {
SQLiteDatabase sql = getDatabaseHandler(context).getWritableDatabase(DatabaseHandler.DB_PASSWD);
int count = -1;
try {
sql.beginTransaction();
count = sql.update(table, values, where, whereArgs);
sql.setTransactionSuccessful();
sql.endTransaction();
} catch (SQLiteException ex) {
Log.e("SQL EXCEPTION", ex.toString());
}
if (count == 0) count = -1;
return count;
}
public void Drop(Context context, String table) {
SQLiteDatabase sql = getDatabaseHandler(context).getWritableDatabase(DatabaseHandler.DB_PASSWD);
sql.execSQL("DROP TABLE IF EXISTS " + table);
}
public void Create(Context context, String table) {
SQLiteDatabase sql = getDatabaseHandler(context).getWritableDatabase(DatabaseHandler.DB_PASSWD);
sql.beginTransaction();
sql.execSQL(table);
sql.setTransactionSuccessful();
sql.endTransaction();
}

Wrapping your inserts in beginTransaction() and endTransaction() is only saving time when you do multiple inserts.
So always save your data to one table at once using the following format, this greatly improves performance:
ArrayList<String> itemsToInsert; //an array of strings you want to insert
db.beginTransaction();
ContentValues values = new ContentValues(1);
for (int i = 0; i < itemsToInsert.size(); i++) {
values.put('field', itemsToInsert.get(i));
db.insert(table, null, values);
}
db.setTransactionSuccessful();
db.endTransaction();
In addition, for selecting from a table, query() is performing slightly better than rawQuery(), but the difference is small.
Als check this article for more background information about SqlLite Performance:
sqlite-insertions

Android provides a new library as part of the architecture components called Room.
official doc says:
The Room persistence library provides an abstraction layer over SQLite
to allow for more robust database access while harnessing the full
power of SQLite.
Room Persistence Library
Save data in a local database using Room
More:
You can use the room with another awesome library (Paging Library) to handle paging and huge data sets
Paging library

How to save (and later retrieve) the selected item of a spinner to SQLite

Alright... I've had enough.
I'm thoroughly frustrated.
So I'd rather ask for help instead of a new monitor.
...And those are VERY expensive here.
Long story short... I have a database. And a table.
private String DEFINE_PROP_TYPES = "CREATE TABLE " + TABLE_PROP_TYPES + "("
+ TABLE_ID + " INTEGER PRIMARY KEY, "
+ TABLE_PROP_TYPE_NAME + " TEXT NOT NULL"
+ ")";
With an 'Adapter' class thrown in for good measure to manage it.
public abstract class DBAdapter
{
static public final String C_COLUMN_ID = "_id";
protected Context context;
protected DBHelper dbHelper;
protected SQLiteDatabase db;
protected String managedTable;
protected String[] columns;
public String getTableManaged()
{
return managedTable;
}
public void setTableManaged(String managedTable)
{
this.managedTable = managedTable;
}
public void setColumns(String[] columns)
{
this.columns = columns;
}
public DBAdapter(Context context)
{
this.context = context;
}
public void close()
{
dbHelper.close();
}
public DBAdapter open() throws SQLException
{
dbHelper = new DBHelper(context);
db = dbHelper.getWritableDatabase();
return this;
}
public Cursor getList()
{
Cursor c = db.query(true, managedTable, columns, null, null, null, null, null, null);
return c;
}
public long insert(ContentValues reg)
{
return 0;
}
}
public class PropTypesDBAdapter extends DBAdapter
{
static public final String C_TABLE_PROP_TYPES = "PROP_TYPES";
static public final String C_COLUMN_ID = "_id",
C_COLUMN_PROP_TYPES_NAME = "re_prop_type";
public PropTypesDBAdapter(Context context)
{
super(context);
this.setTableManaged(C_TABLE_PROP_TYPES);
this.setColumns(new String[] { C_COLUMN_ID,
C_COLUMN_PROP_TYPES_NAME });
}
public long insert(ContentValues reg)
{
if (db == null)
{
open();
}
return db.insert(C_TABLE_PROP_TYPES, null, reg);
}
}
And besides this pile of cute I have an activity class.
With spinners.
public class PropDetailActivity extends Activity implements LocationListener
{
// insert here some blah-blah constants not needed by spinners
private PropDBAdapter mHouses;
private RatingsDBAdapter mRatings;
private PropTypesDBAdapter mPropTypes;
private Cursor mCursorHouses,
mCursorRatings,
mCursorPropTypes;
long mPropType;
private long mPropId;
private Spinner spinnerRating, spinnerType;
AdapterView.OnItemSelectedListener spnLstPropType, spnLstRating;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_house_detail);
Intent intent = getIntent();
Bundle extra = intent.getExtras();
if (extra == null)
{
return;
}
// Figure all view widgets being retrieved here, including...
spinnerRating = (Spinner) findViewById(R.id.spinnerRating);
spinnerType = (Spinner) findViewById(R.id.spinnerType);
// Create adapter and cursor-y things here
mHouses = new PropDBAdapter(this);
mHouses.open();
// And now, for the juicy, deliciously irritating stuff:
String[] from = new String[] { PropTypesDBAdapter.C_COLUMN_PROP_TYPES_NAME };
int[] to = new int[] { android.R.id.text1 };
mPropTypes = new PropTypesDBAdapter(this);
mPropTypes.open();
mCursorPropTypes = mPropTypes.getList();
#SuppressWarnings("deprecation")
SimpleCursorAdapter adapterPropTypes = new SimpleCursorAdapter(this,
android.R.layout.simple_spinner_item,
mCursorPropTypes,
from, /*new String[] { RatingsDBAdapter.C_COLUMN_RATING_NAME }, */
to); /*new int[] { android.R.id.text1 } */
adapterPropTypes.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerType.setAdapter(adapterPropTypes);
spinnerRating.setSelection(pos);
spnLstPropType = new AdapterView.OnItemSelectedListener()
{
#Override
public void onItemSelected(AdapterView<?> parent, View view,
int pos, long id)
{
mPropType = id;
}
#Override
public void onNothingSelected(AdapterView<?> arg0) { }
};
spinnerType.setOnItemSelectedListener(spnLstPropType);
private int getItemPositionById(Cursor c, long id, DBAdapter adapter)
{
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext())
{
if (c.getLong(c.getColumnIndex(DBAdapter.C_COLUMN_ID)) == id)
{
return c.getPosition();
}
}
return 0;
}
private void query(long id)
{
mCursorHouses = mHouses.getRecord(id);
// Figure values being retrieved and set on their widgets instead of this comment... and now...
mPropType = mCursorHouses.getInt(mCursorHouses.getColumnIndex(PropDBAdapter.C_PROP_TYPE_ID));
spinnerType.setSelection(
getItemPositionById(
mCursorRatings,
mCursorHouses.getColumnIndex(PropDBAdapter.C_PROP_TYPE_ID),
mPropTypes
)
);
private void save()
{
ContentValues reg = new ContentValues();
// Read: values being put into 'reg'... eventually it should reach this:
reg.put(PropDBAdapter.C_PROP_TYPE_ID, mPropType);
try
{
if (mFormMode == PropListActivity.C_CREATE)
{
mHouses.insert(reg);
Toast.makeText(PropDetailActivity.this, R.string.house_create_notice, Toast.LENGTH_LONG).show();
}
else if (mFormMode == PropListActivity.C_EDIT)
{
Toast.makeText(PropDetailActivity.this, R.string.house_edit_notice, Toast.LENGTH_LONG).show();
reg.put(PropDBAdapter.C_COLUMN_ID, mPropId);
long resultCode = mHouses.update(reg);
Log.i(this.getClass().toString(), "Database operation result code: " + resultCode);
}
}
catch(SQLException e)
{
Log.i(this.getClass().toString(), e.getMessage());
}
setResult(RESULT_OK);
finish();
}
}
Spinners are being bad boys. Lazy bad boys on top of that.
They do load up the data -a list of real estate property types- they are meant to display.
After some spanking, that is.
But, hoping them to save THE VALUE YOU SELECT to SQLite? And to show THAT EXACT VALUE when fetching stuff back from the database?
Oh, no, no way no how.
They stubbornly stick to displaying always the same value upon activity startup.
So... please... I must draw upon your collective wisdom to save my sorry excuse for a project...
Pleasepleaseplease? :)
(IF you feel like diving into the whole uncut code, here's a GIT repository for you: https://github.com/CruxMDQ/Quoterv3)

Checking your code, I think I found the problem, change the following lines in your query method in PopDetailActivity.java.
For spinnerRating do:
spinnerRating.setSelection(
getItemPositionById(
mCursorRatings,
mCursorHouses.getInt(mCursorHouses.getColumnIndex(PropDBAdapter.C_PROP_RATING_ID)),
mRatings
)
);
and for spinnerType do:
spinnerType.setSelection(
getItemPositionById(
mCursorPropTypes,
mCursorHouses.getInt(mCursorHouses.getColumnIndex(PropDBAdapter.C_PROP_TYPE_ID)),
mPropTypes
)
);
EDIT:
In your query method, you initialize mPropTypeId, with the call to getItemPositionById() but in that call the first parameter should be mCursorPropTypes instead of mCursorHouses

A few things:
(1) I don't really see anywhere above where you actually create a SQLite database or use the SQLiteOpenHelper class to access that data. Take a look at this tutorial. It uses a simple single table set up to store data. Once you create the database it should be easy to read and write from it. Verify that you actually have a database created.
(2) Where are your SQL queries to return the data you're looking for? Even if data is being added you need to make sure you are getting the right data with your Cursor when you're done. If you're getting the same values each time is it possible that you are simply adding new data every time and retrieving the same value with your cursor - i.e. you're not telling the cursor to get the newly added data becuase you keep grabing the same index?
If you need to replace the data that's there you should be using update queries and not inserts.