IDAServerDataset
Overview
The IDAServerDataset interface is used to represent a special type of command that fetches a record set from the database. The interface extends IDASQLCommand, which provides the basic settings for executing commands on the database, and extends it with functionality specific to commands returning record sets. Datasets are usually obtained via IDAConnection or TDASchema and will be implemented by different classes depending on the database driver you are using.
Location
- Unit: uDAServerInterfaces.pas
- Ancestry: IDASQLCommand | IDAServerDataset
Active
Specifies whether the dataset is currently active (open) or not. Setting this property to true will automatically open the dataset, while setting it to false will automatically close it.
property Active: Boolean read write
Close safecall
Closes the dataset
procedure Close
ControlsDisabled safecall
Indicates whether data-aware controls update their display to reflect changes to the dataset.
function ControlsDisabled: Boolean
CurrentRecIdValue
Returns identificator of current record.
property CurrentRecIdValue: Integer read write
Dataset (declared in IDASQLCommand)
Access to the standard VCL TDataSet.
property Dataset: TDataSet read
DisableConstraints safecall
Disables dataset constraints
procedure DisableConstraints
DisableControls safecall
Disables data display in data-aware controls associated with the dataset.
procedure DisableControls
DynamicWhere (declared in IDASQLCommand)
Implementation of Dynamic Where.
property DynamicWhere: TDAWhereBuilder read write
EnableConstraints safecall
Enables dataset constraints
procedure EnableConstraints
EnableControls safecall
Enables data display in data-aware controls associated with the dataset.
procedure EnableControls
Eof
Indicates whether reading the dataset has reached the end of the recordset (EOF = End of File). EOF will only turn true if neither an empty dataset was opened or Next was called while the cursor was already on the last record (it will not turn to true when reaching the last record).
property Eof: Boolean read
Execute safecall (declared in IDASQLCommand)
Performs execution of SQL command.
function Execute: Integer
FieldByName safecall
Finds a field based on its name. If the specified field does not exist, FieldByName raises an exception.
function FieldByName(const aName: string): TDAField
Parameters:
- aName: name of the searched field
FieldCount
Indicates the number of fields contained in the dataset.
property FieldCount: Integer read
Fields
Provides access to all the fields contained in the dataset.
property Fields: TDAFieldCollection read
FieldValues
Provides convenient access to all the fields values of the current record without having to go though the Fields collection property.
property FieldValues[Index: Integer]: Variant read
FindField safecall
Returns an item with the specified name.
function FindField(const aName: string): TDAField
Parameters:
- aName: name of the searched field
IsEmpty
Indicates whether the dataset contains no records.
property IsEmpty: Boolean read
Locate safecall
Locates and activates a record by key values.
function Locate(const KeyFields: string; const KeyValues: Variant; Options: TLocateOptions): Boolean
Parameters:
- KeyFields: The semicolon-separated list of fields.
- KeyValues: Values specified by the Variant or Variant array.
- Options: Indicates whether the search is case insensitive and whether partial matches are supported.
LogicalName
Defines the name of the data table.
property LogicalName: string read write
Lookup safecall
Retrieves the field values from the record that matches the specified search values.
function Lookup(const KeyFields: string; const KeyValues: Variant; const ResultFields: string): Variant
Parameters:
- KeyFields: the semicolon-separated list of fields
- KeyValues: Values specified by the Variant or Variant array.
- ResultFields: The semicolon-separated list of result fields.
Name (declared in IDASQLCommand)
Returns a human-readable name for the command. For commands obtained through a TDASchema component, this will be the name that the command (or data table) was defined under in Schema Modeler. When obtaining a command from an IDAConnection, the name can be specified in the call to NewCommand or NewDataset.
property Name: string read
Names
Returns data table's field name specified by Index
property Names[Index: Integer]: string read
Next safecall
Advances the cursor to the next available record in the dataset. If the current record is the last record available, calling Next will set EOF to indicate the end of the dataset has been reached.
procedure Next
OnAfterExecute (declared in IDASQLCommand)
Fires right after a command was executed.
property OnAfterExecute: TDAAfterExecuteCommandEvent read write
delegate: procedure OnAfterExecute(const Sender: IDASQLCommand; ActualSQL: string; ElapsedMilliseconds: Cardinal)
OnAfterOpen
Fires after dataset was opened
property OnAfterOpen: TDAAfterOpenDatasetEvent read write
delegate: procedure OnAfterOpen(const Sender: IDADataset; ActualSQL: string; ElapsedMilliseconds: Cardinal)
OnBeforeExecute (declared in IDASQLCommand)
Fires just before a command will be executed.
property OnBeforeExecute: TDABeforeExecuteCommandEvent read write
delegate: procedure OnBeforeExecute(const Sender: IDASQLCommand)
OnBeforeOpen
Fires before dataset was opened
property OnBeforeOpen: TDABeforeOpenDatasetEvent read write
delegate: procedure OnBeforeOpen(const Sender: IDADataset)
OnExecuteError (declared in IDASQLCommand)
Fires if error was present during execution of command.
property OnExecuteError: TDAExecuteCommandErrorEvent read write
delegate: procedure OnExecuteError(const Sender: IDASQLCommand; ActualSQL: string; Error: Exception)
OnOpenError
Fired if error was occured duting opening of dataset
property OnOpenError: TDAOpenDatasetErrorEvent read write
delegate: procedure OnOpenError(const Sender: IDADataset; ActualSQL: string; Error: Exception)
Open safecall
Opens the dataset and prepares it for fetching records from the database.
procedure Open
OrderBy
Represents the collection of OrderBy statements.
property OrderBy: TDAOrderByCollection read write
ParamByName safecall (declared in IDASQLCommand)
Locates a specific parameter, based on its name. If no matching parameter is defined, an exception will be raised.
function ParamByName(const aName: string): TDAParam
Parameters:
- aName: name of the parameter
Params (declared in IDASQLCommand)
Provides access to the list of parameters defined for the command.
property Params: TDAParamCollection read
Prepared (declared in IDASQLCommand)
Specifies whether the SQL statement has been prepared for execution on the database (true) or not (false). Setting this property to true will automatically prepare the statement. Preparing statements on the database server allows for faster execution, especially if the statement will be executed multiple times, as the server will not need to re-parse the SQL text for every execution. Please refer to your database system's documentation for more information on preparing statements.
Note that changing the SQL or Where properties will automatically un-prepare the statement.
property Prepared: Boolean read write
RecordCount
Returns the counf of records
property RecordCount: Integer read
RefreshParams safecall (declared in IDASQLCommand)
Refreshes the list of parameters defined for the command based on the actual parameter names found in the SQL statement and Where clause.
procedure RefreshParams
RowRecIdValue
Returns record ID
property RowRecIdValue: Integer read
SQL (declared in IDASQLCommand)
Defines the SQL statement to be executed.
property SQL: string read write
SQLContainsDynamicWhere safecall (declared in IDASQLCommand)
Checks if SQL contains Dynamic Where macros.
function SQLContainsDynamicWhere: Boolean
Active
Specifies whether the dataset is currently active (open) or not. Setting this property to true will automatically open the dataset, while setting it to false will automatically close it.
property Active: Boolean read write
CurrentRecIdValue
Returns identificator of current record.
property CurrentRecIdValue: Integer read write
Dataset (declared in IDASQLCommand)
Access to the standard VCL TDataSet.
property Dataset: TDataSet read
DynamicWhere (declared in IDASQLCommand)
Implementation of Dynamic Where.
property DynamicWhere: TDAWhereBuilder read write
Eof
Indicates whether reading the dataset has reached the end of the recordset (EOF = End of File). EOF will only turn true if neither an empty dataset was opened or Next was called while the cursor was already on the last record (it will not turn to true when reaching the last record).
property Eof: Boolean read
FieldCount
Indicates the number of fields contained in the dataset.
property FieldCount: Integer read
Fields
Provides access to all the fields contained in the dataset.
property Fields: TDAFieldCollection read
FieldValues
Provides convenient access to all the fields values of the current record without having to go though the Fields collection property.
property FieldValues[Index: Integer]: Variant read
IsEmpty
Indicates whether the dataset contains no records.
property IsEmpty: Boolean read
LogicalName
Defines the name of the data table.
property LogicalName: string read write
Name (declared in IDASQLCommand)
Returns a human-readable name for the command. For commands obtained through a TDASchema component, this will be the name that the command (or data table) was defined under in Schema Modeler. When obtaining a command from an IDAConnection, the name can be specified in the call to NewCommand or NewDataset.
property Name: string read
Names
Returns data table's field name specified by Index
property Names[Index: Integer]: string read
OrderBy
Represents the collection of OrderBy statements.
property OrderBy: TDAOrderByCollection read write
Params (declared in IDASQLCommand)
Provides access to the list of parameters defined for the command.
property Params: TDAParamCollection read
Prepared (declared in IDASQLCommand)
Specifies whether the SQL statement has been prepared for execution on the database (true) or not (false). Setting this property to true will automatically prepare the statement. Preparing statements on the database server allows for faster execution, especially if the statement will be executed multiple times, as the server will not need to re-parse the SQL text for every execution. Please refer to your database system's documentation for more information on preparing statements.
Note that changing the SQL or Where properties will automatically un-prepare the statement.
property Prepared: Boolean read write
RecordCount
Returns the counf of records
property RecordCount: Integer read
RowRecIdValue
Returns record ID
property RowRecIdValue: Integer read
SQL (declared in IDASQLCommand)
Defines the SQL statement to be executed.
property SQL: string read write
Close safecall
Closes the dataset
procedure Close
ControlsDisabled safecall
Indicates whether data-aware controls update their display to reflect changes to the dataset.
function ControlsDisabled: Boolean
DisableConstraints safecall
Disables dataset constraints
procedure DisableConstraints
DisableControls safecall
Disables data display in data-aware controls associated with the dataset.
procedure DisableControls
EnableConstraints safecall
Enables dataset constraints
procedure EnableConstraints
EnableControls safecall
Enables data display in data-aware controls associated with the dataset.
procedure EnableControls
Execute safecall (declared in IDASQLCommand)
Performs execution of SQL command.
function Execute: Integer
FieldByName safecall
Finds a field based on its name. If the specified field does not exist, FieldByName raises an exception.
function FieldByName(const aName: string): TDAField
Parameters:
- aName: name of the searched field
FindField safecall
Returns an item with the specified name.
function FindField(const aName: string): TDAField
Parameters:
- aName: name of the searched field
Locate safecall
Locates and activates a record by key values.
function Locate(const KeyFields: string; const KeyValues: Variant; Options: TLocateOptions): Boolean
Parameters:
- KeyFields: The semicolon-separated list of fields.
- KeyValues: Values specified by the Variant or Variant array.
- Options: Indicates whether the search is case insensitive and whether partial matches are supported.
Lookup safecall
Retrieves the field values from the record that matches the specified search values.
function Lookup(const KeyFields: string; const KeyValues: Variant; const ResultFields: string): Variant
Parameters:
- KeyFields: the semicolon-separated list of fields
- KeyValues: Values specified by the Variant or Variant array.
- ResultFields: The semicolon-separated list of result fields.
Next safecall
Advances the cursor to the next available record in the dataset. If the current record is the last record available, calling Next will set EOF to indicate the end of the dataset has been reached.
procedure Next
Open safecall
Opens the dataset and prepares it for fetching records from the database.
procedure Open
ParamByName safecall (declared in IDASQLCommand)
Locates a specific parameter, based on its name. If no matching parameter is defined, an exception will be raised.
function ParamByName(const aName: string): TDAParam
Parameters:
- aName: name of the parameter
RefreshParams safecall (declared in IDASQLCommand)
Refreshes the list of parameters defined for the command based on the actual parameter names found in the SQL statement and Where clause.
procedure RefreshParams
SQLContainsDynamicWhere safecall (declared in IDASQLCommand)
Checks if SQL contains Dynamic Where macros.
function SQLContainsDynamicWhere: Boolean
OnAfterExecute (declared in IDASQLCommand)
Fires right after a command was executed.
property OnAfterExecute: TDAAfterExecuteCommandEvent read write
delegate: procedure OnAfterExecute(const Sender: IDASQLCommand; ActualSQL: string; ElapsedMilliseconds: Cardinal)
OnAfterOpen
Fires after dataset was opened
property OnAfterOpen: TDAAfterOpenDatasetEvent read write
delegate: procedure OnAfterOpen(const Sender: IDADataset; ActualSQL: string; ElapsedMilliseconds: Cardinal)
OnBeforeExecute (declared in IDASQLCommand)
Fires just before a command will be executed.
property OnBeforeExecute: TDABeforeExecuteCommandEvent read write
delegate: procedure OnBeforeExecute(const Sender: IDASQLCommand)
OnBeforeOpen
Fires before dataset was opened
property OnBeforeOpen: TDABeforeOpenDatasetEvent read write
delegate: procedure OnBeforeOpen(const Sender: IDADataset)
OnExecuteError (declared in IDASQLCommand)
Fires if error was present during execution of command.
property OnExecuteError: TDAExecuteCommandErrorEvent read write
delegate: procedure OnExecuteError(const Sender: IDASQLCommand; ActualSQL: string; Error: Exception)
OnOpenError
Fired if error was occured duting opening of dataset
property OnOpenError: TDAOpenDatasetErrorEvent read write
delegate: procedure OnOpenError(const Sender: IDADataset; ActualSQL: string; Error: Exception)
- IDAConnection and TDASchema methods.
- Database Drivers