protected override void OnCreate(Bundle bundle) {
base.OnCreate(bundle);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.Main);
// Get our button from the layout resource,
// and attach an event to it
Button button = FindViewById<Button>(Resource.Id.MyButton);
button.Click += delegate { button.Text = string.Format("{0} clicks!", count++); };
#region ADDED TO SAMPLE TO DEMONSTRATE Portable.Data.Sqlite
string myTableName = "TestTable1";
string sql;
//Instantiate my "crypt engine"
this.AppCryptEngine = this.AppCryptEngine ?? new FakeCryptEngine(this.AppPassword);
#region Part 1 - ADO - Create a table, add a record, add a column, add encrypted data, read back data
using (var dbConn = new SqliteAdoConnection(this.SqliteConnection, this.AppCryptEngine)) {
Console.WriteLine("PART 1 - Doing ADO stuff");
//Create the table if it doesn't exist
sql = "CREATE TABLE IF NOT EXISTS " + myTableName + " (IdColumn INTEGER PRIMARY KEY AUTOINCREMENT, DateTimeColumn DATETIME, TextColumn TEXT);";
using (var cmd = new SqliteCommand(sql, dbConn)) {
dbConn.SafeOpen();
cmd.ExecuteNonQuery();
Console.WriteLine("Table [" + myTableName + "] created (if it didn't exist).");
}
//Add a record
sql = "INSERT INTO " + myTableName + " (DateTimeColumn, TextColumn) VALUES (@date, @text);";
int newRowId;
using (var cmd = new SqliteCommand(sql, dbConn)) {
cmd.Parameters.Add(new SqliteParameter("@date", DateTime.Now));
cmd.Parameters.Add(new SqliteParameter("@text", "Hello SQLite."));
dbConn.SafeOpen();
newRowId = Convert.ToInt32(cmd.ExecuteReturnRowId()); //Note: INTEGER columns in SQLite are always long/Int64 - including ID columns, so converting to int
Console.WriteLine("A record with ID " + newRowId.ToString() + " was created in table [" + myTableName + "].");
}
//Read the datetime column on the oldest record
sql = "SELECT [DateTimeColumn] FROM " + myTableName + " ORDER BY [DateTimeColumn] LIMIT 1;";
using (var cmd = new SqliteCommand(sql, dbConn)) {
dbConn.SafeOpen();
DateTime oldest = Convert.ToDateTime(cmd.ExecuteScalar());
Console.WriteLine("The oldest record in table [" + myTableName + "] has timestamp: " + oldest.ToString());
}
//Add an encrypted column to the table
//NOTE: There is no benefit to creating the column as SQLite datatype ENCRYPTED vs. TEXT
// It is actually a TEXT column - but I think it is nice to set it to type ENCRYPTED for future purposes.
// Hopefully a future version of SQLitePCL will make it easy to figure out if a column is defined as ENCRYPTED or TEXT
// (right now, it identifies both as TEXT)
sql = "ALTER TABLE " + myTableName + " ADD COLUMN EncryptedColumn ENCRYPTED;";
//Note: This column shouldn't exist until the above sql is run, since I just created the table above. But if this application has been run multiple times,
// the column may already exist in the table - so I need to check for it.
bool columnAlreadyExists = false;
#region Check for column
using (var checkCmd = new SqliteCommand(dbConn)) {
checkCmd.CommandText = "PRAGMA table_info (" + myTableName + ");";
dbConn.SafeOpen();
using (var checkDr = new SqliteDataReader(checkCmd)) {
while (checkDr.Read()) {
if (checkDr.GetString("NAME") == "EncryptedColumn") {
Console.WriteLine("The [EncryptedColumn] column already exists.");
columnAlreadyExists = true;
break;
}
}
}
}
#endregion
if (!columnAlreadyExists) {
using (var cmd = new SqliteCommand(sql, dbConn)) {
dbConn.SafeOpen();
cmd.ExecuteNonQuery();
Console.WriteLine("The [EncryptedColumn] column was created in table [" + myTableName + "].");
}
}
//Add a record with an encrypted column value
sql = "INSERT INTO " + myTableName + " (DateTimeColumn, TextColumn, EncryptedColumn) VALUES (@date, @text, @encrypted);";
using (var cmd = new SqliteCommand(sql, dbConn)) {
cmd.Parameters.Add(new SqliteParameter("@date", DateTime.Now));
cmd.Parameters.Add(new SqliteParameter("@text", "Hello data."));
cmd.AddEncryptedParameter(new SqliteParameter("@encrypted",
Tuple.Create<string, string, string>("Hello", "encrypted", "data")));
dbConn.SafeOpen();
newRowId = Convert.ToInt32(cmd.ExecuteReturnRowId()); //Note: INTEGER columns in SQLite are always long/Int64 - including ID columns, so converting to int
Console.WriteLine("A record featuring encrypted data with ID " + newRowId.ToString() + " was created in table [" + myTableName + "].");
}
//Get the value of the encrypted column
sql = "SELECT [EncryptedColumn] FROM " + myTableName + " WHERE [IdColumn] = @id;";
using (var cmd = new SqliteCommand(sql, dbConn)) {
cmd.Parameters.Add(new SqliteParameter("@id", newRowId));
dbConn.SafeOpen();
string encryptedColumnValue = cmd.ExecuteScalar().ToString();
var decryptedValue = this.AppCryptEngine.DecryptObject<Tuple<string, string, string>>(encryptedColumnValue);
Console.WriteLine("The actual (encrypted) value of the [EncryptedColumn] column of record ID " + newRowId.ToString() + " is: " + encryptedColumnValue);
Console.WriteLine("The decrypted value of the [EncryptedColumn] column of record ID " + newRowId.ToString() + " is: " +
decryptedValue.Item1 + " " + decryptedValue.Item2 + " " + decryptedValue.Item3);
}
//Using a SqliteDataReader and GetDecrypted<T> to get all of the encrypted values
sql = "SELECT [IdColumn], [DateTimeColumn], [EncryptedColumn] FROM " + myTableName + ";";
using (var cmd = new SqliteCommand(sql, dbConn)) {
dbConn.SafeOpen();
using (var dr = new SqliteDataReader(cmd)) {
while (dr.Read()) {
var sb = new StringBuilder();
sb.Append("ID: " + dr.GetInt32("IdColumn").ToString());
sb.Append(" - Timestamp: " + dr.GetDateTime("DateTimeColumn").ToString());
//IMPORTANT: By default, GetDecrypted<T> will throw an exception on a NULL column value. You can specify DbNullHandling.ReturnTypeDefaultValue
// to return the default value of the specified type - as in default(T) - when a NULL column value is encountered, if you choose.
var decryptedValue = dr.GetDecrypted<Tuple<string, string, string>>("EncryptedColumn", DbNullHandling.ReturnTypeDefaultValue);
sb.Append(" - Value: " + ((decryptedValue == null) ? "NULL" :
decryptedValue.Item1 + " " + decryptedValue.Item2 + " " + decryptedValue.Item3));
Console.WriteLine(sb.ToString());
}
}
}
}
#endregion
#region Part 2 - EncryptedTable - Create an encrypted table to hold SampleDataItem objects, and read and write data
long numRecords;
using (var dbConn = new SqliteAdoConnection(this.SqliteConnection, this.AppCryptEngine)) {
Console.WriteLine(" ");
Console.WriteLine("PART 2 - Doing EncryptedTable stuff");
//Creating the encrypted table, adding some items/records
using (var encTable = new EncryptedTable<SampleDataItem>(this.AppCryptEngine, dbConn)) {
//Shouldn't need to call CheckDbTable manually, but I am going to check to see if there are
// records in the table, so I need to make sure the table exists
//This will check the table and create the table and/or any missing columns if needed.
encTable.CheckDbTable();
//Check to see how many records are in the table now
numRecords = SampleDataItem.GetNumRecords(dbConn, encTable.TableName);
Console.WriteLine("(1) There are currently " + numRecords.ToString() + " records in the table: " + encTable.TableName);
foreach (var item in ExampleData.GetData().Where(i => i.LastName != "Johnson")) {
encTable.AddItem(item);
}
Console.WriteLine("(2) There are currently {0} items to be written to the encrypted table: {1}",
encTable.TempItems.Where(i => i.IsDirty).Count(), encTable.TableName);
//Note that at this point in the code, nothing new has been written to the table yet.
// The table will be updated on encTable.Dispose (in this case, that happens automatically at the end of this using() code
// block) or we could force it now with encTable.WriteItemChanges()
//encTable.WriteItemChanges();
}
//Adding a couple more records...
using (var encTable = new EncryptedTable<SampleDataItem>(this.AppCryptEngine, dbConn)) {
//Because encTable was disposed above, we should now see records in the table
numRecords = SampleDataItem.GetNumRecords(dbConn, encTable.TableName);
Console.WriteLine("(3) There are currently " + numRecords.ToString() + " records in the table: " + encTable.TableName);
//Here is one way to add an item to the table - immediately
// (no need to type out 'immediateWriteToTable:' - but just wanted to show what the 'true' was for)
encTable.AddItem(ExampleData.GetData().Where(i => i.FirstName == "Bob").Single(), immediateWriteToTable: true);
//Another way to add items to the table - wait until WriteItemChanges() or WriteChangesAndFlush() or encTable.Dispose()
// is called
encTable.AddItem(ExampleData.GetData().Where(i => i.FirstName == "Joan").Single(), immediateWriteToTable: false);
encTable.AddItem(ExampleData.GetData().Where(i => i.FirstName == "Ned").Single());
//Should only see one more record - Joan and Ned haven't been written yet
numRecords = SampleDataItem.GetNumRecords(dbConn, encTable.TableName);
Console.WriteLine("(4) There are currently " + numRecords.ToString() + " records in the table: " + encTable.TableName);
//Let's see which items we have in memory right now
foreach (var item in encTable.TempItems) {
Console.WriteLine("In memory: ID#{0} {1} {2} - Status: {3}", item.Id, item.FirstName, item.LastName, item.SyncStatus);
}
//We can use WriteItemChanges() - writes any in-memory item changes to the table
//encTable.WriteItemChanges();
//OR WriteChangesAndFlush() writes any in-memory items to the table, and then drops any in-memory items and/or in-memory index of the table
//Normally, only items that are out-of-sync with the table are written, forceWriteAll causes all items (whether they have changed or not)
// to be written
encTable.WriteChangesAndFlush(forceWriteAll: true);
//How many items in memory now?
Console.WriteLine("After WriteChangesAndFlush() there are now {0} items in memory.", encTable.TempItems.Count());
//How many records in the table?
numRecords = SampleDataItem.GetNumRecords(dbConn, encTable.TableName);
Console.WriteLine("After WriteChangesAndFlush() there are now {0} records in the table.", numRecords.ToString());
}
//Reading and searching for items/records
using (var encTable = new EncryptedTable<SampleDataItem>(this.AppCryptEngine, dbConn)) {
//Doing a GetItems() with an empty TableSearch (like the line below) will get all items
List<SampleDataItem> allItems = encTable.GetItems(new TableSearch());
foreach (var item in allItems) {
Console.WriteLine("In table: ID#{0} {1} {2}", item.Id, item.FirstName, item.LastName);
}
//Let's just get one item - exceptionOnMissingItem: true will throw an exception if the item wasn't found
// in the table; with exceptionOnMissingItem: false, we will just get a null
SampleDataItem singleItem = encTable.GetItem(allItems.First().Id, exceptionOnMissingItem: true);
Console.WriteLine("Found via ID: ID#{0} {1} {2}", singleItem.Id, singleItem.FirstName, singleItem.LastName);
//Because we did a full table GetItems() above, we should have a nice, searchable index of all of the
// items in the table. But let's check it and re-build if necessary
encTable.CheckFullTableIndex(rebuildIfExpired: true);
//Otherwise, we could just force a rebuild of the searchable index
// encTable.BuildFullTableIndex();
//So, the easy way to find matching items, based on the full table index is to pass in a TableSearch
List<SampleDataItem> matchingItems = encTable.GetItems(new TableSearch {
SearchType = TableSearchType.MatchAll, //Items must match all search criteria
MatchItems = {
new TableSearchItem("LastName", "Johnson", SearchItemMatchType.IsEqualTo),
new TableSearchItem("FirstName", "Ned", SearchItemMatchType.DoesNotContain)
}
});
foreach (var item in matchingItems) {
Console.WriteLine("Found via search: ID#{0} {1} {2}", item.Id, item.FirstName, item.LastName);
}
//Let's see what is in this "full table index" anyway
foreach (var item in encTable.FullTableIndex.Index) {
Console.WriteLine("Indexed item ID: " + item.Key.ToString());
foreach (var value in item.Value) {
Console.WriteLine(" - Searchable value: {0} = {1}", value.Key ?? "", value.Value ?? "");
}
}
//Let's remove/delete a record from the table (with immediate removal)
Console.WriteLine("Deleting record: ID#{0} {1} {2}", singleItem.Id, singleItem.FirstName, singleItem.LastName);
encTable.RemoveItem(singleItem.Id, immediateWriteToTable: true);
//Let's see what is actually in the table
Console.WriteLine("Records in the table " + encTable.TableName + " - ");
sql = "select * from " + encTable.TableName;
using (var cmd = new SqliteCommand(sql, dbConn)) {
using (SqliteDataReader reader = cmd.ExecuteReader()) {
while (reader.Read()) {
var record = new StringBuilder();
foreach (Portable.Data.Sqlite.TableColumn column in encTable.TableColumns.Values.OrderBy(tc => tc.ColumnOrder)) {
if (column.ColumnName == "Id") { record.Append(column.ColumnName + ": " + reader[column.ColumnName].ToString()); }
else {
record.Append(" - " + column.ColumnName + ": " + (reader[column.ColumnName].ToString() ?? ""));
}
}
Console.WriteLine(record.ToString());
}
}
}
}
}
#endregion
Console.WriteLine("Done.");
//Pop up a message saying we are done
var dialog = new AlertDialog.Builder(this);
dialog.SetMessage("If you can see this message, then the sample Portable.Data.Sqlite code ran correctly. " +
"Take a look at the code in the 'MainActivity.cs' file, and compare it to what you are seeing in the IDE Output window. " +
"And have a nice day...");
dialog.SetCancelable(false);
dialog.SetPositiveButton("OK", delegate { });
dialog.Create().Show();
#endregion
}
private void Cleanup(SqliteAdoConnection cnn) {
if (_disposeConnection)
cnn.Dispose();
_transaction = null;
_scope = null;
}
internal SqliteEnlistment(SqliteAdoConnection cnn, Transaction scope) {
_transaction = cnn.BeginTransaction();
_scope = scope;
_disposeConnection = false;
_scope.EnlistVolatile(this, Portable.Transactions.EnlistmentOptions.None);
}
/// <summary>
/// Commits the current transaction.
/// </summary>
public override void Commit() {
IsValid(true);
if (_cnn._transactionLevel - 1 == 0) {
using (SqliteCommand cmd = _cnn.CreateCommand()) {
cmd.CommandText = "COMMIT";
cmd.ExecuteNonQuery();
}
}
_cnn._transactionLevel--;
_cnn = null;
}
/// <summary>
/// Constructs the transaction object, binding it to the supplied connection
/// </summary>
/// <param name="connection">The connection to open a transaction on</param>
/// <param name="deferredLock">TRUE to defer the writelock, or FALSE to lock immediately</param>
internal SqliteTransaction(SqliteAdoConnection connection, bool deferredLock) {
_cnn = connection;
_version = _cnn._version;
_level = (deferredLock == true) ? IsolationLevel.ReadCommitted : IsolationLevel.Serializable;
if (_cnn._transactionLevel++ == 0) {
try {
using (SqliteCommand cmd = _cnn.CreateCommand()) {
if (!deferredLock)
cmd.CommandText = "BEGIN IMMEDIATE";
else
cmd.CommandText = "BEGIN";
cmd.ExecuteNonQuery();
}
}
catch (SqliteException) {
_cnn._transactionLevel--;
_cnn = null;
throw;
}
}
}
//A little static method to check and see how many records are in the encrypted table,
// that I will use multiple times in the sample code.
// No need to include something like this in your implementations of EncryptedTableItem
public static long GetNumRecords(SqliteAdoConnection dbConn, string tableName) {
string sql = "SELECT COUNT(*) FROM " + tableName + ";";
using (var cmd = new SqliteCommand(sql, dbConn)) {
dbConn.SafeOpen();
return (long)cmd.ExecuteScalar();
}
}
/// <summary>
/// Clears the connection pool associated with the connection. Any other active connections using the same database file
/// will be discarded instead of returned to the pool when they are closed.
/// </summary>
/// <param name="connection"></param>
public static void ClearPool(SqliteAdoConnection connection) {
if (connection._sql == null) return;
connection._sql.ClearPool();
}
/// <summary>
/// When the database connection is closed, all commands linked to this connection are automatically reset.
/// </summary>
public override void Close() {
if (_sql != null) {
if (_enlistment != null) {
// If the connection is enlisted in a transaction scope and the scope is still active,
// we cannot truly shut down this connection until the scope has completed. Therefore make a
// hidden connection temporarily to hold open the connection until the scope has completed.
var cnn = new SqliteAdoConnection(_sqliteDbConnection, _cryptEngine) {
_sql = this._sql,
_transactionLevel = this._transactionLevel,
_enlistment = this._enlistment,
_connectionState = this._connectionState,
_version = this._version
};
cnn._enlistment._transaction._cnn = cnn;
cnn._enlistment._disposeConnection = true;
_sql = null;
_enlistment = null;
}
if (_sql != null) {
_sql.Dispose();
//_sql.Close();
}
_sql = null;
_transactionLevel = 0;
}
OnStateChange(ConnectionState.Closed);
}
/// <summary>
/// Creates a clone of the connection. All attached databases and user-defined functions are cloned. If the existing connection is open, the cloned connection
/// will also be opened.
/// </summary>
/// <returns></returns>
public object Clone() {
var cloned = new SqliteAdoConnection(_sqliteDbConnection, _cryptEngine);
if (this.State == ConnectionState.Open) cloned.Open();
return cloned;
}
/// <summary>
/// Clones the settings and connection string from an existing connection. If the existing connection is already open, this
/// function will open its own connection, enumerate any attached databases of the original connection, and automatically
/// attach to them.
/// </summary>
/// <param name="connection"></param>
public SqliteAdoConnection(SqliteAdoConnection connection)
: this(connection._sqliteDbConnection, connection._cryptEngine) {
if (connection.State == ConnectionState.Open) {
Open();
}
}
/// <summary>
/// Disposes the transaction. If it is currently active, any changes are rolled back.
/// </summary>
protected override void Dispose(bool disposing) {
if (disposing) {
lock (this) {
if (IsValid(false))
Rollback();
_cnn = null;
}
}
base.Dispose(disposing);
}
internal static void IssueRollback(SqliteAdoConnection cnn) {
using (SqliteCommand cmd = cnn.CreateCommand()) {
cmd.CommandText = "ROLLBACK";
cmd.ExecuteNonQuery();
}
}
/// <summary>
/// Rolls back the active transaction.
/// </summary>
public override void Rollback() {
IsValid(true);
IssueRollback(_cnn);
_cnn._transactionLevel = 0;
_cnn = null;
}