Midware TMWTable
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Contents
Overview
unit | MWdatSet.pas |
TMWTable component is much like standard Delphi TTable or TQuery components. TMWTable is used as an interface between data and your program or visual interface.
TMWTable is a TDataSet descendent so you can use it with data-aware controls such as TDBEdit and TDBGrid. Just like you use TQuery or TTable.
TMWTable is an interface that present MidWare communication buffer ( TMWBufer component) as a standard Delphi data table. It let you navigate thru all records and fields. You can and locate data, insert, delete or edit data. TMWTable has no storage for data: all data is stored in TMWBuffer component.
TMWTable has no knowledge of table structure. You must specify it using FieldLayout property. You can fill this property at design time if you know what it will be at runtime, or you may fill it at runtime once you know the value. The value may be known at runtime because your client application query the application server for field layout. You may also sent field layout in first record in result set, feed it to the property and then delete it from result set.
Properties
Active | Active property is TRUE when TMWTable is opened and FALSE when TMWTable is closed. | |
AppSrvClient | To execute a request at design time, TMWTable need an TAppSrvClient component which will handle communication with MidWare application server. | |
AutoCalcFields | Set AutoCalcFields to control when the OnCalcFields event is triggered to update calculated fields during dataset processing. | |
CanModify | CanModify readonly property returns TMWTable ReadOnly value. | |
Data | Data property is a link to TMWBuffer component used to hold all data. | |
FieldLayout | FieldLayout property is used to describe columns content. | |
FunctionCode | FunctionCode and Params properties are the design time request. It's main purpose is to populate data aware controls link to TMWTable at design time. It can also be executed at runtime using ExecuteRequest. | |
MWBufferFieldCount | The number of fields. Based on FieldLayout property. | |
ReadOnly | ReadOnly property is used to get or set TMWTable read only status. See also CanModify. | |
RecordSize | The record size property gives the size of the record. | |
Params | FunctionCode and Params properties are the design time request. | |
TimeOut | When executing a request at design time, TMWTable will stop waiting for answer after Timeout seconds. |
Methods
Close | Close the communication with the application server. | |
CreateBlobStream | Call CreateBlobStream to obtain a stream for reading and writing the value of the field specified by the Field parameter. | |
DesignTimeRequest | DesignTimeRequest procedure will execute the request specified at design time. | |
ExecuteRequest | Call ExecuteRequest procedure to execute design time request. | |
Locate | Implements a method for searching a dataset for a specified record and makes that record the current record. | |
Lookup | Implements a method to retrieve field values from a record that matches specified search values. | |
Send | Send a FunctionCode and Request (parmeters) to the application server. |
Events
AfterCancel | Occurs after an application completes a request to cancel modifications to the current record. | |
AfterClose | Occurs after an application closes a dataset. | |
AfterDelete | Occurs after an application deletes a record. | |
AfterEdit | Occurs after an application starts editing a record. | |
AfterInsert | Occurs after an application inserts a new record. | |
AfterOpen | Occurs after an application completes opening a dataset and before any data access occurs. | |
AfterScroll | Occurs after an application scrolls from one record to another. | |
BeforeCancel | Occurs before an application executes a request to cancel changes to the current record. | |
BeforeClose | Occurs before an application executes a request to close the dataset. | |
BeforeDelete | Occurs before an application attempts to delete the current record. | |
BeforeEdit | Occurs before an application enters edit mode for the current record. | |
BeforeInsert | Occurs before an application enters insert mode. | |
BeforeOpen | Occurs before an application executes a request to open a dataset. | |
BeforeScroll | Occurs before an application scrolls from one record to another. | |
OnCalcField | Occurs when an application recalculates calculated fields. | |
OnDisplayInfo | Occurs when TMWTable wants to display debugging informations. | |
OnDeleteError | Occurs when an application attempts to delete a record and an exception is raised. | |
OnEditError | Occurs when an application attempts to modify or insert a record and an exception is raised. | |
OnNewRecord | Occurs when an application inserts or appends a new dataset record. | |
OnPostError | Occurs when an application attempts to modify or insert a record and an exception is raised. | |
OnRequestDone | Occurs when design time request has been satisfied and a result set is available. |