Code:
/ Dotnetfx_Win7_3.5.1 / Dotnetfx_Win7_3.5.1 / 3.5.1 / DEVDIV / depot / DevDiv / releases / whidbey / NetFXspW7 / ndp / fx / src / Data / System / Data / Odbc / DbDataRecord.cs / 1 / DbDataRecord.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //[....] //[....] //----------------------------------------------------------------------------- using System; using System.ComponentModel; //Component using System.Data; using System.Runtime.InteropServices; //Marshal using System.Reflection; //Missing namespace System.Data.Odbc { sealed internal class DbSchemaInfo { internal DbSchemaInfo() { } internal string _name; internal string _typename; internal Type _type; internal ODBC32.SQL_TYPE? _dbtype; internal object _scale; internal object _precision; // extension to allow BindCol // internal int _columnlength; // internal int _valueOffset; // offset to the data in the row buffer internal int _lengthOffset; // offset to the length in the row buffer internal ODBC32.SQL_C _sqlctype; // need this to bind the value internal ODBC32.SQL_TYPE _sql_type; // need that to properly marshal the value } ///////////////////////////////////////////////////////////////////////////// // Cache // // This is a on-demand cache, only caching what the user requests. // The reational is that for ForwardOnly access (the default and LCD of drivers) // we cannot obtain the data more than once, and even GetData(0) (to determine is-null) // still obtains data for fixed lenght types. // So simple code like: // if(!rReader.IsDBNull(i)) // rReader.GetInt32(i) // // Would fail, unless we cache on the IsDBNull call, and return the cached // item for GetInt32. This actually improves perf anyway, (even if the driver could // support it), since we are not making a seperate interop call... // We do not cache all columns, so reading out of order is still not // ///////////////////////////////////////////////////////////////////////////// sealed internal class DbCache { //Data private bool[] _isBadValue; private DbSchemaInfo[] _schema; private object[] _values; private OdbcDataReader _record; internal int _count; internal bool _randomaccess = true; //Constructor internal DbCache(OdbcDataReader record, int count) { _count = count; _record = record; _randomaccess = (!record.IsBehavior(CommandBehavior.SequentialAccess)); _values = new object[count]; _isBadValue = new bool[count]; } //Accessor internal object this[int i] { get { if(_isBadValue[i]) { OverflowException innerException = (OverflowException)Values[i]; throw new OverflowException(innerException.Message, innerException); } return Values[i]; } set { Values[i] = value; _isBadValue[i] = false; } } internal int Count { get { return _count; } } internal void InvalidateValue(int i) { _isBadValue[i] = true; } internal object[] Values { get { return _values; } } internal object AccessIndex(int i) { //Note: We could put this directly in this[i], instead of having an explicit overload. //However that means that EVERY access into the cache takes the hit of checking, so //something as simple as the following code would take two hits. It's nice not to //have to take the hit when you know what your doing. // // if(cache[i] == null) // .... // return cache[i]; object[] values = this.Values; if(_randomaccess) { //Random //Means that the user can ask for the values int any order (ie: out of order). // In order to acheive this on a forward only stream, we need to actually // retreive all the value in between so they can go back to values they've skipped for(int c = 0; c < i; c++) { if(values[c] == null) { values[c] = _record.GetValue(c); } } } return values[i]; } internal DbSchemaInfo GetSchema(int i) { if(_schema == null) { _schema = new DbSchemaInfo[Count]; } if(_schema[i] == null) { _schema[i] = new DbSchemaInfo(); } return _schema[i]; } internal void FlushValues() { //Set all objects to null (to explcitly release them) //Note: SchemaInfo remains the same for all rows - no need to reget those... int count = _values.Length; for(int i = 0; i < count; ++i) { _values[i] = null; } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. //------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //[....] //[....] //----------------------------------------------------------------------------- using System; using System.ComponentModel; //Component using System.Data; using System.Runtime.InteropServices; //Marshal using System.Reflection; //Missing namespace System.Data.Odbc { sealed internal class DbSchemaInfo { internal DbSchemaInfo() { } internal string _name; internal string _typename; internal Type _type; internal ODBC32.SQL_TYPE? _dbtype; internal object _scale; internal object _precision; // extension to allow BindCol // internal int _columnlength; // internal int _valueOffset; // offset to the data in the row buffer internal int _lengthOffset; // offset to the length in the row buffer internal ODBC32.SQL_C _sqlctype; // need this to bind the value internal ODBC32.SQL_TYPE _sql_type; // need that to properly marshal the value } ///////////////////////////////////////////////////////////////////////////// // Cache // // This is a on-demand cache, only caching what the user requests. // The reational is that for ForwardOnly access (the default and LCD of drivers) // we cannot obtain the data more than once, and even GetData(0) (to determine is-null) // still obtains data for fixed lenght types. // So simple code like: // if(!rReader.IsDBNull(i)) // rReader.GetInt32(i) // // Would fail, unless we cache on the IsDBNull call, and return the cached // item for GetInt32. This actually improves perf anyway, (even if the driver could // support it), since we are not making a seperate interop call... // We do not cache all columns, so reading out of order is still not // ///////////////////////////////////////////////////////////////////////////// sealed internal class DbCache { //Data private bool[] _isBadValue; private DbSchemaInfo[] _schema; private object[] _values; private OdbcDataReader _record; internal int _count; internal bool _randomaccess = true; //Constructor internal DbCache(OdbcDataReader record, int count) { _count = count; _record = record; _randomaccess = (!record.IsBehavior(CommandBehavior.SequentialAccess)); _values = new object[count]; _isBadValue = new bool[count]; } //Accessor internal object this[int i] { get { if(_isBadValue[i]) { OverflowException innerException = (OverflowException)Values[i]; throw new OverflowException(innerException.Message, innerException); } return Values[i]; } set { Values[i] = value; _isBadValue[i] = false; } } internal int Count { get { return _count; } } internal void InvalidateValue(int i) { _isBadValue[i] = true; } internal object[] Values { get { return _values; } } internal object AccessIndex(int i) { //Note: We could put this directly in this[i], instead of having an explicit overload. //However that means that EVERY access into the cache takes the hit of checking, so //something as simple as the following code would take two hits. It's nice not to //have to take the hit when you know what your doing. // // if(cache[i] == null) // .... // return cache[i]; object[] values = this.Values; if(_randomaccess) { //Random //Means that the user can ask for the values int any order (ie: out of order). // In order to acheive this on a forward only stream, we need to actually // retreive all the value in between so they can go back to values they've skipped for(int c = 0; c < i; c++) { if(values[c] == null) { values[c] = _record.GetValue(c); } } } return values[i]; } internal DbSchemaInfo GetSchema(int i) { if(_schema == null) { _schema = new DbSchemaInfo[Count]; } if(_schema[i] == null) { _schema[i] = new DbSchemaInfo(); } return _schema[i]; } internal void FlushValues() { //Set all objects to null (to explcitly release them) //Note: SchemaInfo remains the same for all rows - no need to reget those... int count = _values.Length; for(int i = 0; i < count; ++i) { _values[i] = null; } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- Light.cs
- ObjectDataSourceEventArgs.cs
- BulletedListEventArgs.cs
- XmlSchemaInferenceException.cs
- CriticalExceptions.cs
- OracleParameterCollection.cs
- CompareValidator.cs
- PageAdapter.cs
- TextElementAutomationPeer.cs
- DocumentPageViewAutomationPeer.cs
- DocumentViewerBaseAutomationPeer.cs
- DrawingCollection.cs
- contentDescriptor.cs
- ComPlusTypeValidator.cs
- RuntimeConfigLKG.cs
- WorkflowInlining.cs
- DockPanel.cs
- ValueType.cs
- DSASignatureDeformatter.cs
- BaseDataBoundControl.cs
- DataView.cs
- WindowsFormsSectionHandler.cs
- HttpCacheParams.cs
- TypedTableHandler.cs
- ConnectionManagementElementCollection.cs
- ListViewCancelEventArgs.cs
- TreeView.cs
- MetadataHelper.cs
- FlowDocumentPageViewerAutomationPeer.cs
- DateBoldEvent.cs
- TripleDES.cs
- State.cs
- LookupBindingPropertiesAttribute.cs
- coordinator.cs
- StagingAreaInputItem.cs
- CodeObjectCreateExpression.cs
- CacheAxisQuery.cs
- DynamicAttribute.cs
- InvalidPrinterException.cs
- PackWebRequestFactory.cs
- ManagementObjectSearcher.cs
- RichTextBox.cs
- SQLMoneyStorage.cs
- SqlDataSourceStatusEventArgs.cs
- XPathNodeIterator.cs
- PrimitiveCodeDomSerializer.cs
- _NestedMultipleAsyncResult.cs
- NavigationExpr.cs
- FlowDocumentPage.cs
- WebPartChrome.cs
- DropShadowEffect.cs
- ToolStripPanelDesigner.cs
- EasingQuaternionKeyFrame.cs
- GrabHandleGlyph.cs
- AllMembershipCondition.cs
- MissingFieldException.cs
- ToolStripDropDown.cs
- ApplicationId.cs
- WebCategoryAttribute.cs
- GridView.cs
- ObjectItemCachedAssemblyLoader.cs
- RelationshipConverter.cs
- CngAlgorithm.cs
- LicenseException.cs
- MailAddressCollection.cs
- DispatcherHookEventArgs.cs
- ExtenderProvidedPropertyAttribute.cs
- WindowsClaimSet.cs
- InkPresenter.cs
- configsystem.cs
- ItemList.cs
- BamlCollectionHolder.cs
- ContextConfiguration.cs
- OracleLob.cs
- WeakReferenceList.cs
- DrawingGroup.cs
- GlobalizationSection.cs
- _WinHttpWebProxyDataBuilder.cs
- StateMachineAction.cs
- Style.cs
- TextEmbeddedObject.cs
- isolationinterop.cs
- ScrollBar.cs
- DataGridCheckBoxColumn.cs
- MailSettingsSection.cs
- Funcletizer.cs
- SQLInt64Storage.cs
- EntityDataSourceDesigner.cs
- TrackingRecord.cs
- ImageBrush.cs
- LinqExpressionNormalizer.cs
- XamlStyleSerializer.cs
- DocumentReferenceCollection.cs
- DataSetFieldSchema.cs
- CompilerParameters.cs
- GradientStopCollection.cs
- EmptyStringExpandableObjectConverter.cs
- XsltException.cs
- BuildProvider.cs
- StringComparer.cs