VirtualDAC

TCustomVirtualQuery Members

TCustomVirtualQuery class overview.

Properties

Name Description

BaseSQL (inherited from TCustomDADataSet)

 Used to return SQL text without any changes performed by AddWhere, SetOrderBy, and FilterSQL.

CachedUpdates (inherited from TMemDataSet)

 Used to enable or disable the use of cached updates for a dataset.

Conditions (inherited from TCustomDADataSet)

 Used to add WHERE conditions to a query

Connection (inherited from TCustomDADataSet)

 Used to specify a connection object to use to connect to a data store.

DataTypeMap (inherited from TCustomDADataSet)

 Used to set data type mapping rules

Debug (inherited from TCustomDADataSet)

 Used to display the statement that is being executed and the values and types of its parameters.

DetailFields (inherited from TCustomDADataSet)

 Used to specify the fields that correspond to the foreign key fields from MasterFields when building master/detail relationship.

Disconnected (inherited from TCustomDADataSet)

 Used to keep dataset opened after connection is closed.

FetchRows (inherited from TCustomDADataSet)

 Used to define the number of rows to be transferred across the network at the same time.

FilterSQL (inherited from TCustomDADataSet)

 Used to change the WHERE clause of SELECT statement and reopen a query.

FinalSQL (inherited from TCustomDADataSet)

 Used to return SQL text with all changes performed by AddWhere, SetOrderBy, and FilterSQL, and with expanded macros.

IndexFieldNames (inherited from TMemDataSet)

 Used to get or set the list of fields on which the recordset is sorted.

IsQuery (inherited from TCustomDADataSet)

 Used to check whether SQL statement returns rows.

KeyExclusive (inherited from TMemDataSet)

 Specifies the upper and lower boundaries for a range.

KeyFields (inherited from TCustomDADataSet)

 Used to build SQL statements for the SQLDelete, SQLInsert, and SQLUpdate properties if they were empty before updating the database.

LocalConstraints (inherited from TMemDataSet)

 Used to avoid setting the Required property of a TField component for NOT NULL fields at the time of opening TMemDataSet.

LocalUpdate (inherited from TMemDataSet)

 Used to prevent implicit update of rows on database server.

MacroCount (inherited from TCustomDADataSet)

 Used to get the number of macros associated with the Macros property.

Macros (inherited from TCustomDADataSet)

 Makes it possible to change SQL queries easily.

MasterFields (inherited from TCustomDADataSet)

 Used to specify the names of one or more fields that are used as foreign keys for dataset when establishing detail/master relationship between it and the dataset specified in MasterSource.

MasterSource (inherited from TCustomDADataSet)

 Used to specify the data source component which binds current dataset to the master one.

Options

 Used to specify the behaviour of TVirtualQuery object.

ParamCheck (inherited from TCustomDADataSet)

 Used to specify whether parameters for the Params property are generated automatically after the SQL property was changed.

ParamCount (inherited from TCustomDADataSet)

 Used to indicate how many parameters are there in the Params property.

Params (inherited from TCustomDADataSet)

 Used to view and set parameter names, values, and data types dynamically.

Prepared (inherited from TMemDataSet)

 Determines whether a query is prepared for execution or not.

Ranged (inherited from TMemDataSet)

 Indicates whether a range is applied to a dataset.

ReadOnly (inherited from TCustomDADataSet)

 Used to prevent users from updating, inserting, or deleting data in the dataset.

RefreshOptions (inherited from TCustomDADataSet)

 Used to indicate when the editing record is refreshed.

RowsAffected (inherited from TCustomDADataSet)

 Used to indicate the number of rows which were inserted, updated, or deleted during the last query operation.

SourceDataSets

 Contains a collection of source datasets for querying data.

SQL (inherited from TCustomDADataSet)

 Used to provide a SQL statement that a query component executes when its Open method is called.

SQLDelete (inherited from TCustomDADataSet)

 Used to specify a SQL statement that will be used when applying a deletion to a record.

SQLInsert (inherited from TCustomDADataSet)

 Used to specify the SQL statement that will be used when applying an insertion to a dataset.

SQLLock (inherited from TCustomDADataSet)

 Used to specify a SQL statement that will be used to perform a record lock.

SQLRecCount (inherited from TCustomDADataSet)

 Used to specify the SQL statement that is used to get the record count when opening a dataset.

SQLRefresh (inherited from TCustomDADataSet)

 Used to specify a SQL statement that will be used to refresh current record by calling the TCustomDADataSet.RefreshRecord procedure.

SQLUpdate (inherited from TCustomDADataSet)

 Used to specify a SQL statement that will be used when applying an update to a dataset.

UniDirectional (inherited from TCustomDADataSet)

 Used if an application does not need bidirectional access to records in the result set.

UpdateRecordTypes (inherited from TMemDataSet)

 Used to indicate the update status for the current record when cached updates are enabled.

UpdatesPending (inherited from TMemDataSet)

 Used to check the status of the cached updates buffer.

Methods

Name Description

AddWhere (inherited from TCustomDADataSet)

 Adds condition to the WHERE clause of SELECT statement in the SQL property.

ApplyRange (inherited from TMemDataSet)

 Applies a range to the dataset.

ApplyUpdates (inherited from TMemDataSet)

 Overloaded. Writes dataset's pending cached updates to a database.

BreakExec (inherited from TCustomDADataSet)

 Breaks execution of the SQL statement on the server.

CancelRange (inherited from TMemDataSet)

 Removes any ranges currently in effect for a dataset.

CancelUpdates (inherited from TMemDataSet)

 Clears all pending cached updates from cache and restores dataset in its prior state.

CloneCursor (inherited from TCustomDADataSet)

 Shares data from another dataset.

CommitUpdates (inherited from TMemDataSet)

 Clears the cached updates buffer.

CreateBlobStream (inherited from TCustomDADataSet)

 Used to obtain a stream for reading data from or writing data to a BLOB field, specified by the Field parameter.

DeferredPost (inherited from TMemDataSet)

 Makes permanent changes to the database server.

DeleteWhere (inherited from TCustomDADataSet)

 Removes WHERE clause from the SQL property and assigns the BaseSQL property.

EditRangeEnd (inherited from TMemDataSet)

 Enables changing the ending value for an existing range.

EditRangeStart (inherited from TMemDataSet)

 Enables changing the starting value for an existing range.

Execute (inherited from TCustomDADataSet)

 Overloaded. Executes a SQL statement on the server.

Executing (inherited from TCustomDADataSet)

 Indicates whether SQL statement is still being executed.

Fetched (inherited from TCustomDADataSet)

 Used to find out whether TCustomDADataSet has fetched all rows.

Fetching (inherited from TCustomDADataSet)

 Used to learn whether TCustomDADataSet is still fetching rows.

FetchingAll (inherited from TCustomDADataSet)

 Used to learn whether TCustomDADataSet is fetching all rows to the end.

FindKey (inherited from TCustomDADataSet)

 Searches for a record which contains specified field values.

FindNearest (inherited from TCustomDADataSet)

 Moves the cursor to a specific record or to the first record in the dataset that matches or is greater than the values specified in the KeyValues parameter.

FindParam (inherited from TCustomDADataSet)

 Determines if a parameter with the specified name exists in a dataset.

GetBlob (inherited from TMemDataSet)

 Overloaded. Retrieves TBlob object for a field or current record when only its name or the field itself is known.

GetDataType (inherited from TCustomDADataSet)

 Returns internal field types defined in the MemData and accompanying modules.

GetFieldObject (inherited from TCustomDADataSet)

 Returns a multireference shared object from field.

GetFieldPrecision (inherited from TCustomDADataSet)

 Retrieves the precision of a number field.

GetFieldScale (inherited from TCustomDADataSet)

 Retrieves the scale of a number field.

GetKeyFieldNames (inherited from TCustomDADataSet)

 Provides a list of available key field names.

GetOrderBy (inherited from TCustomDADataSet)

 Retrieves an ORDER BY clause from a SQL statement.

GotoCurrent (inherited from TCustomDADataSet)

 Sets the current record in this dataset similar to the current record in another dataset.

Locate (inherited from TMemDataSet)

 Overloaded. Searches a dataset for a specific record and positions the cursor on it.

LocateEx (inherited from TMemDataSet)

 Overloaded. Excludes features that don't need to be included to the TMemDataSet.Locate method of TDataSet.

Lock (inherited from TCustomDADataSet)

 Locks the current record.

MacroByName (inherited from TCustomDADataSet)

 Finds a macro with the specified name.

ParamByName (inherited from TCustomDADataSet)

 Sets or uses parameter information for a specific parameter based on its name.

Prepare (inherited from TCustomDADataSet)

 Allocates, opens, and parses cursor for a query.

RefreshRecord (inherited from TCustomDADataSet)

 Actualizes field values for the current record.

RestoreSQL (inherited from TCustomDADataSet)

 Restores the SQL property modified by AddWhere and SetOrderBy.

RestoreUpdates (inherited from TMemDataSet)

 Marks all records in the cache of updates as unapplied.

RevertRecord (inherited from TMemDataSet)

 Cancels changes made to the current record when cached updates are enabled.

SaveSQL (inherited from TCustomDADataSet)

 Saves the SQL property value to BaseSQL.

SaveToXML (inherited from TMemDataSet)

 Overloaded. Saves the current dataset data to a file or a stream in the XML format compatible with ADO format.

SetOrderBy (inherited from TCustomDADataSet)

 Builds an ORDER BY clause of a SELECT statement.

SetRange (inherited from TMemDataSet)

 Sets the starting and ending values of a range, and applies it.

SetRangeEnd (inherited from TMemDataSet)

 Indicates that subsequent assignments to field values specify the end of the range of rows to include in the dataset.

SetRangeStart (inherited from TMemDataSet)

 Indicates that subsequent assignments to field values specify the start of the range of rows to include in the dataset.

SQLSaved (inherited from TCustomDADataSet)

 Determines if the SQL property value was saved to the BaseSQL property.

UnLock (inherited from TCustomDADataSet)

 Releases a record lock.

UnPrepare (inherited from TMemDataSet)

 Frees the resources allocated for a previously prepared query on the server and client sides.

UpdateResult (inherited from TMemDataSet)

 Reads the status of the latest call to the ApplyUpdates method while cached updates are enabled.

UpdateStatus (inherited from TMemDataSet)

 Indicates the current update status for the dataset when cached updates are enabled.

Events

Name Description

AfterExecute (inherited from TCustomDADataSet)

 Occurs after a component has executed a query to database.

AfterFetch (inherited from TCustomDADataSet)

 Occurs after dataset finishes fetching data from server.

AfterUpdateExecute (inherited from TCustomDADataSet)

 Occurs after executing insert, delete, update, lock and refresh operations.

BeforeFetch (inherited from TCustomDADataSet)

 Occurs before dataset is going to fetch block of records from the server.

BeforeUpdateExecute (inherited from TCustomDADataSet)

 Occurs before executing insert, delete, update, lock, and refresh operations.

OnRegisterCollations

 Occurs when the connection is opened to register the user-defined collation used in the query text.

OnRegisterFunctions

 Occurs when the query is opened to register the user-defined functions used in the query text.

OnUpdateError (inherited from TMemDataSet)

 Occurs when an exception is generated while cached updates are applied to a database.

OnUpdateRecord (inherited from TMemDataSet)

 Occurs when a single update component can not handle the updates.
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