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Reduced memory footprint. Closes #65.
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Command and reader objects are immediately disposed in order to reduce
the memory footprint. This is particular relevant on mobile devices
with small amounts of available memory.
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@hisystems
hisystems committed Aug 2, 2012
1 parent 72f9a0c commit 2f28f28
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Showing 2 changed files with 87 additions and 76 deletions.
32 changes: 26 additions & 6 deletions Database/ConnectionScope.cs
View file
Expand Up @@ -25,15 +25,24 @@ public class ConnectionScope : IDisposable
/// If a connection is already opened then the already open connection is utilised.
/// </summary>
public ConnectionScope(Database database)
: this(GetConnection(database))
{
if (database == null)
throw new ArgumentNullException();

connection = database.Connection;

connection.Start();
}

/// <summary>
/// Ensures that a new connection is opened.
/// If a connection is already opened then the already open connection is utilised.
/// </summary>
internal ConnectionScope(Database.ConnectionController connection)
{
if (connection == null)
throw new ArgumentNullException();

this.connection = connection;

connection.Start();
}

/// --------------------------------------------------------------------------------
/// <summary>
/// Executes the SQL statement.
Expand Down Expand Up @@ -104,5 +113,16 @@ public void Dispose()

GC.SuppressFinalize(this);
}

/// <summary>
/// Called by constructor.
/// </summary>
private static Database.ConnectionController GetConnection(Database database)
{
if (database == null)
throw new ArgumentNullException();

return database.Connection;
}
}
}
131 changes: 61 additions & 70 deletions Database/Database.cs
View file
Expand Up @@ -1085,17 +1085,13 @@ public SQL.SQLFieldValues ObjectLockRecord(IDatabaseObjects objCollection, IData
if (objSubset != null && !objSubset.IsEmpty)
objSelect.Where.Add(objSubset);

IDataReader objReader = this.Transactions.Execute(objSelect);
SQL.SQLFieldValues objFieldValues;

if (objReader.Read())
objFieldValues = FieldValuesFromDataReader(objCollection, objReader);
else
throw new Exceptions.ObjectDoesNotExistException(objCollection, objItem.DistinctValue);

objReader.Close();

return objFieldValues;
using (var objReader = this.Transactions.Execute(objSelect))
{
if (objReader.Read())
return FieldValuesFromDataReader(objCollection, objReader);
else
throw new Exceptions.ObjectDoesNotExistException(objCollection, objItem.DistinctValue);
}
}

/// --------------------------------------------------------------------------------
Expand Down Expand Up @@ -1916,13 +1912,14 @@ internal bool InTransactionMode
/// </summary>
/// --------------------------------------------------------------------------------
public object ExecuteScalar(SQL.ISQLStatement objSQLStatement)
{
IDataReader objDataReader = ExecuteInternal(pobjConnection, objSQLStatement);

if (objDataReader.Read())
return objDataReader[0];
else
return null;
{
using (var objDataReader = ExecuteInternal(pobjConnection, objSQLStatement))
{
if (objDataReader.Read())
return objDataReader[0];
else
return null;
}
}

/// --------------------------------------------------------------------------------
Expand All @@ -1935,20 +1932,17 @@ public object ExecuteScalar(SQL.ISQLStatement objSQLStatement)
/// </summary>
/// --------------------------------------------------------------------------------
public object ExecuteScalarWithConnect(SQL.ISQLStatement objSQLStatement)
{
object result;

this.Start();

IDataReader objDataReader = ExecuteInternal(pobjConnection, objSQLStatement);
if (objDataReader.Read())
result = objDataReader[0];
else
result = null;

this.Finished();

return result;
{
using (var connectionScope = new ConnectionScope(this))
{
using (var objDataReader = connectionScope.Execute(objSQLStatement))
{
if (objDataReader.Read())
return objDataReader[0];
else
return null;
}
}
}

/// --------------------------------------------------------------------------------
Expand Down Expand Up @@ -2004,11 +1998,8 @@ public int ExecuteNonQuery(SQL.ISQLStatement[] objSQLStatements)
[Obsolete("Use DatabaseObjects.ConnectionScope")]
public int ExecuteNonQueryWithConnect(SQL.ISQLStatement objSQLStatement)
{
this.Start();
int result = this.ExecuteNonQuery(objSQLStatement);
this.Finished();

return result;
using (var connectionScope = new ConnectionScope(this))
return connectionScope.ExecuteNonQuery(objSQLStatement);
}

/// --------------------------------------------------------------------------------
Expand All @@ -2020,11 +2011,8 @@ public int ExecuteNonQueryWithConnect(SQL.ISQLStatement objSQLStatement)
[Obsolete("Use DatabaseObjects.ConnectionScope")]
public int ExecuteNonQueryWithConnect(SQL.ISQLStatement[] objSQLStatements)
{
this.Start();
int result = this.ExecuteNonQuery(new SQL.SQLStatements(objSQLStatements));
this.Finished();

return result;
using (var connectionScope = new ConnectionScope(this))
return connectionScope.ExecuteNonQuery(new SQL.SQLStatements(objSQLStatements));
}

protected virtual IDataReader ExecuteInternal(IDbConnection objConnection, SQL.ISQLStatement objSQLStatement)
Expand All @@ -2034,22 +2022,24 @@ protected virtual IDataReader ExecuteInternal(IDbConnection objConnection, SQL.I

objSQLStatement.ConnectionType = peConnectionType;
string strSQL = objSQLStatement.SQL;

var command = objConnection.CreateCommand();
command.CommandText = strSQL;

if (pobjTransactions.Count > 0)
command.Transaction = pobjTransactions.Peek(); //Only used for SQLServerCompactEdition
IDataReader reader;

using (var command = objConnection.CreateCommand())
{
command.CommandText = strSQL;

IDataReader reader;
if (pobjTransactions.Count > 0)
command.Transaction = pobjTransactions.Peek(); //Only used for SQLServerCompactEdition

try
{
reader = command.ExecuteReader();
}
catch (Exception ex)
{
throw new Exceptions.DatabaseObjectsException("Execute failed: " + strSQL, ex);
try
{
reader = command.ExecuteReader();
}
catch (Exception ex)
{
throw new Exceptions.DatabaseObjectsException("Execute failed: " + strSQL, ex);
}
}

OnStatementExecuted(objSQLStatement);
Expand All @@ -2061,27 +2051,28 @@ protected virtual int ExecuteNonQueryInternal(IDbConnection objConnection, SQL.I
{
if (objConnection == null)
throw new Exceptions.DatabaseObjectsException("Connection is not open, call Database.Connection.Start() or Database.Transactions.Begin()");

objSQLStatement.ConnectionType = peConnectionType;
string strSQL = objSQLStatement.SQL;
int rowAffected;

var command = objConnection.CreateCommand();
command.CommandText = strSQL;

if (pobjTransactions.Count > 0)
command.Transaction = pobjTransactions.Peek(); //Only used for SQLServerCompactEdition
using (var command = objConnection.CreateCommand())
{
command.CommandText = strSQL;

int rowAffected;
if (pobjTransactions.Count > 0)
command.Transaction = pobjTransactions.Peek(); //Only used for SQLServerCompactEdition

try
{
rowAffected = command.ExecuteNonQuery();
}
catch (Exception ex)
{
throw new Exceptions.DatabaseObjectsException("ExecuteNonQuery failed: " + strSQL, ex);
try
{
rowAffected = command.ExecuteNonQuery();
}
catch (Exception ex)
{
throw new Exceptions.DatabaseObjectsException("ExecuteNonQuery failed: " + strSQL, ex);
}
}

OnStatementExecuted(objSQLStatement);

return rowAffected;
Expand Down

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