TDAConnectionManager

 

Standard component constructor

constructor Create(aOwner: TComponent)

Parameters:

• aOwner: Owner

---

Copies the contents of another, similar object.

procedure Assign(Source: TPersistent)

Parameters:

• Source: Instance whose properties will be copied

---

Validates the connection manager properties.

procedure CheckProperties

---

Clears all properties.

procedure Clear

---

Removes all connections from the pool. Note that calling ClearPool will not automatically close connections that are currently active; any active connections will remain active until they are released.

procedure ClearPool

---

Maintains the list of connections (a.k.a. connection strings) defined in the dictionary.

property Connections: TDAConnectionCollection read write

---

Creates a new connection with given parameters.

function CreateNewConnection(const ConnectionName: string; OpenConnection: Boolean; const UserID: string; const Password: string): IDAConnection

Parameters:

• ConnectionName: Connection name.
• OpenConnection: Auto-open connection
• UserID: user name
• Password: password

---

Must reference the application's TDADriverManager instance, which maintains a list of all known database drivers, whether statically linked or dynamically loaded.

property DriverManager: TDADriverManager read write

---

Gets the default connection name.

function GetDefaultConnectionName: string

---

procedure LoadFromFile(const aFileName: string)

Parameters:

• aFileName:

---

Restores the component data from file via LoadFromStream.

procedure LoadFromFile(const aFileName: string; aFormat: TDAPersistFormat)

Parameters:

• aFileName: Valid name of the readable file
• aFormat: See TDAPersistFormat

---

procedure LoadFromJson(aJson: ROUTF8String)

Parameters:

• aJson:

---

procedure LoadFromStream(aStream: TStream)

Parameters:

• aStream:

---

Restores the component data stored in the given stream.

procedure LoadFromStream(aStream: TStream; aFormat: TDAPersistFormat)

Parameters:

• aStream: Data storage
• aFormat: See TDAPersistFormat

---

procedure LoadFromString(aValue: ROUTF8String)

Parameters:

• aValue:

---

Uses aXML as storage to load from.

procedure LoadFromXml(aXML: ROUTF8String)

Parameters:

• aXML: Xml text

---

Defines the maximum number of connections allows in the pool for each connection string. The value of the PoolBehaviour property will control how the pools will behave if the maximum number of connections is reached.

property MaxPoolSize: Cardinal read write

---

Returns a new connection, either from the pool or a freshly created one.

function NewConnection(const aConnectionName: string; OpenConnection: Boolean; const UserID: string; const Password: string): IDAConnection

Parameters:

• aConnectionName: Connection name.
• OpenConnection: Auto-open connection
• UserID: user name
• Password: password

---

Forwards notification messages to all owned components.

procedure Notification(AComponent: TComponent; Operation: TOperation)

Parameters:

• AComponent: component
• Operation: operation

---

Fires whenever a connection was acquired. This connection could have been freshly created (in which case the OnConnectionCreated event will also fire), or be obtained from a pool.

property OnConnectionAcquired: TDAConnectionNotifyEvent read write
delegate:  procedure OnConnectionAcquired(Sender: TDAConnectionManager; const Connection: IDAConnection)

---

Fires whenever a new connection was created. The event will not fire if a pooled connection was reused.

property OnConnectionCreated: TDAConnectionNotifyEvent read write
delegate:  procedure OnConnectionCreated(Sender: TDAConnectionManager; const Connection: IDAConnection)

---

Fires if an attempt to acquire a new connection has failed, for whatever reason.

property OnConnectionFailure: TDAConnectionFailureEvent read write
delegate:  procedure OnConnectionFailure(Sender: TDAConnectionManager; Ex: Exception)

---

Fires whenever a connection was released.

property OnConnectionReleased: TDAConnectionNotifyEvent read write
delegate:  procedure OnConnectionReleased(Sender: TDAConnectionManager; const Connection: IDAConnection)

---

Fires when a pooled connection has timed out and will be removed from the pool.

property OnConnectionTimedOut: TDAConnectionTimeoutEvent read write
delegate:  procedure OnConnectionTimedOut(Sender: TDAConnectionManager)

---

Allows to perform commit or rollback manually at releasing of connection.

property OnCustomPoolTransactionBehavior: TDAConnectionNotifyEvent read write
delegate:  procedure OnCustomPoolTransactionBehavior(Sender: TDAConnectionManager; const Connection: IDAConnection)

---

This procedure maintains cleanup of cached connections.

procedure OnTimerTick(CurrentTickCount: Cardinal)

Parameters:

• CurrentTickCount: not used

---

Fires when unknown macro variable is found. it can be usable when user-defined variables are used inside sql or Dynamic Where expression.

property OnUnknownMacroVariable: TDAUnknownMacroVariableEvent read write
delegate:  procedure OnUnknownMacroVariable(Sender: TObject; const Name: string; var Value: string)

---

Manages the pool behavior when the maximum number of connections has been reached. The three available options include:

• The call to NewConnection will fail with an exception.
• The call to NewConnection will wait until another connection is freed, and it will then return a connection.
• The call to NewConnection will return nil.

property PoolBehaviour: TDAPoolBehaviour read write

---

Enables connection pooling. Default is true. If enabled, the connection manager will maintain a pool of reusable connections, to avoid the overhead of creating and destroying database connections for each request. If disabled, each call to NewConnection will create a new connection to the back-end database, which will be closed when it is released.

property PoolingEnabled: Boolean read write

---

Returns the current size of the connection pool.

property PoolSize: Integer read

---

After this number seconds of inactivity old connections will be removed from the pool and closed. Default is 60 seconds.

property PoolTimeoutSeconds: Cardinal read write

---

Decides how the pool handles connections that are returned to the pool with an active transaction. The three available options include:

• No action will be taken.
• The transaction will be rolled back, losing all changes (recommended).
• The transaction will be committed, applying all changes to the underlying database.

property PoolTransactionBehaviour: TDAPoolTransactionBehaviour read write

---

Releases given connection.

procedure ReleaseConnection(const Conn: IDAConnection)

Parameters:

• Conn: Given connection.

---

Restores specific information not accessible as usual properties.

procedure RestoreNonStreamableProperties(const TempStorage: TPointerArray)

Parameters:

• TempStorage: Array to point to additional values

---

Forwards notification messages to all owned components.

procedure ROFreeNotification(aComponent: TComponent)

Parameters:

• aComponent: component

---

Forwards notification messages to all owned components.

procedure RORemoveFreeNotification(aComponent: TComponent)

Parameters:

• aComponent: component

---

Stores specific information not accessible as usual properties.

procedure SaveNonStreamableProperties(var TempStorage: TPointerArray)

Parameters:

• TempStorage: Array to point to additional values

---

Stores the component data into file via SaveToStream.

procedure SaveToFile(const aFileName: string; aFormat: TDAPersistFormat)

Parameters:

• aFileName: Valid name of the writable file
• aFormat: See TDAPersistFormat

---

Stores the component data into the given stream.

procedure SaveToStream(aStream: TStream; aFormat: TDAPersistFormat)

Parameters:

• aStream: Data storage
• aFormat: See TDAPersistFormat

---

Forwards notification messages to all owned components.

procedure SendRemoveNotification(aComponent: TComponent)

Parameters:

• aComponent: component

---

Specifies default strategy - First In, First Out (FIFO) or Last In, First Out (LIFO)

property Strategy: TConnectionManagerStrategy read write

---

Sets the number of seconds that NewConnection will wait between attempts to acquire a new connection, if the pool ix maximized out and PoolBehaviour is set to pbWait.

property WaitIntervalSeconds: Cardinal read write

 

Maintains the list of connections (a.k.a. connection strings) defined in the dictionary.

property Connections: TDAConnectionCollection read write

---

Must reference the application's TDADriverManager instance, which maintains a list of all known database drivers, whether statically linked or dynamically loaded.

property DriverManager: TDADriverManager read write

---

Defines the maximum number of connections allows in the pool for each connection string. The value of the PoolBehaviour property will control how the pools will behave if the maximum number of connections is reached.

property MaxPoolSize: Cardinal read write

---

Manages the pool behavior when the maximum number of connections has been reached. The three available options include:

• The call to NewConnection will fail with an exception.
• The call to NewConnection will wait until another connection is freed, and it will then return a connection.
• The call to NewConnection will return nil.

property PoolBehaviour: TDAPoolBehaviour read write

---

Enables connection pooling. Default is true. If enabled, the connection manager will maintain a pool of reusable connections, to avoid the overhead of creating and destroying database connections for each request. If disabled, each call to NewConnection will create a new connection to the back-end database, which will be closed when it is released.

property PoolingEnabled: Boolean read write

---

Returns the current size of the connection pool.

property PoolSize: Integer read

---

After this number seconds of inactivity old connections will be removed from the pool and closed. Default is 60 seconds.

property PoolTimeoutSeconds: Cardinal read write

---

Decides how the pool handles connections that are returned to the pool with an active transaction. The three available options include:

• No action will be taken.
• The transaction will be rolled back, losing all changes (recommended).
• The transaction will be committed, applying all changes to the underlying database.

property PoolTransactionBehaviour: TDAPoolTransactionBehaviour read write

---

Specifies default strategy - First In, First Out (FIFO) or Last In, First Out (LIFO)

property Strategy: TConnectionManagerStrategy read write

---

Sets the number of seconds that NewConnection will wait between attempts to acquire a new connection, if the pool ix maximized out and PoolBehaviour is set to pbWait.

property WaitIntervalSeconds: Cardinal read write

 

Standard component constructor

constructor Create(aOwner: TComponent)

Parameters:

• aOwner: Owner

---

Copies the contents of another, similar object.

procedure Assign(Source: TPersistent)

Parameters:

• Source: Instance whose properties will be copied

---

Validates the connection manager properties.

procedure CheckProperties

---

Clears all properties.

procedure Clear

---

Removes all connections from the pool. Note that calling ClearPool will not automatically close connections that are currently active; any active connections will remain active until they are released.

procedure ClearPool

---

Creates a new connection with given parameters.

function CreateNewConnection(const ConnectionName: string; OpenConnection: Boolean; const UserID: string; const Password: string): IDAConnection

Parameters:

• ConnectionName: Connection name.
• OpenConnection: Auto-open connection
• UserID: user name
• Password: password

---

Gets the default connection name.

function GetDefaultConnectionName: string

---

procedure LoadFromFile(const aFileName: string)

Parameters:

• aFileName:

---

Restores the component data from file via LoadFromStream.

procedure LoadFromFile(const aFileName: string; aFormat: TDAPersistFormat)

Parameters:

• aFileName: Valid name of the readable file
• aFormat: See TDAPersistFormat

---

procedure LoadFromJson(aJson: ROUTF8String)

Parameters:

• aJson:

---

procedure LoadFromStream(aStream: TStream)

Parameters:

• aStream:

---

Restores the component data stored in the given stream.

procedure LoadFromStream(aStream: TStream; aFormat: TDAPersistFormat)

Parameters:

• aStream: Data storage
• aFormat: See TDAPersistFormat

---

procedure LoadFromString(aValue: ROUTF8String)

Parameters:

• aValue:

---

Uses aXML as storage to load from.

procedure LoadFromXml(aXML: ROUTF8String)

Parameters:

• aXML: Xml text

---

Returns a new connection, either from the pool or a freshly created one.

function NewConnection(const aConnectionName: string; OpenConnection: Boolean; const UserID: string; const Password: string): IDAConnection

Parameters:

• aConnectionName: Connection name.
• OpenConnection: Auto-open connection
• UserID: user name
• Password: password

---

Forwards notification messages to all owned components.

procedure Notification(AComponent: TComponent; Operation: TOperation)

Parameters:

• AComponent: component
• Operation: operation

---

This procedure maintains cleanup of cached connections.

procedure OnTimerTick(CurrentTickCount: Cardinal)

Parameters:

• CurrentTickCount: not used

---

Releases given connection.

procedure ReleaseConnection(const Conn: IDAConnection)

Parameters:

• Conn: Given connection.

---

Restores specific information not accessible as usual properties.

procedure RestoreNonStreamableProperties(const TempStorage: TPointerArray)

Parameters:

• TempStorage: Array to point to additional values

---

Forwards notification messages to all owned components.

procedure ROFreeNotification(aComponent: TComponent)

Parameters:

• aComponent: component

---

Forwards notification messages to all owned components.

procedure RORemoveFreeNotification(aComponent: TComponent)

Parameters:

• aComponent: component

---

Stores specific information not accessible as usual properties.

procedure SaveNonStreamableProperties(var TempStorage: TPointerArray)

Parameters:

• TempStorage: Array to point to additional values

---

Stores the component data into file via SaveToStream.

procedure SaveToFile(const aFileName: string; aFormat: TDAPersistFormat)

Parameters:

• aFileName: Valid name of the writable file
• aFormat: See TDAPersistFormat

---

Stores the component data into the given stream.

procedure SaveToStream(aStream: TStream; aFormat: TDAPersistFormat)

Parameters:

• aStream: Data storage
• aFormat: See TDAPersistFormat

---

Forwards notification messages to all owned components.

procedure SendRemoveNotification(aComponent: TComponent)

Parameters:

• aComponent: component

 

Fires whenever a connection was acquired. This connection could have been freshly created (in which case the OnConnectionCreated event will also fire), or be obtained from a pool.

property OnConnectionAcquired: TDAConnectionNotifyEvent read write
delegate:  procedure OnConnectionAcquired(Sender: TDAConnectionManager; const Connection: IDAConnection)

---

Fires whenever a new connection was created. The event will not fire if a pooled connection was reused.

property OnConnectionCreated: TDAConnectionNotifyEvent read write
delegate:  procedure OnConnectionCreated(Sender: TDAConnectionManager; const Connection: IDAConnection)

---

Fires if an attempt to acquire a new connection has failed, for whatever reason.

property OnConnectionFailure: TDAConnectionFailureEvent read write
delegate:  procedure OnConnectionFailure(Sender: TDAConnectionManager; Ex: Exception)

---

Fires whenever a connection was released.

property OnConnectionReleased: TDAConnectionNotifyEvent read write
delegate:  procedure OnConnectionReleased(Sender: TDAConnectionManager; const Connection: IDAConnection)

---

Fires when a pooled connection has timed out and will be removed from the pool.

property OnConnectionTimedOut: TDAConnectionTimeoutEvent read write
delegate:  procedure OnConnectionTimedOut(Sender: TDAConnectionManager)

---

Allows to perform commit or rollback manually at releasing of connection.

property OnCustomPoolTransactionBehavior: TDAConnectionNotifyEvent read write
delegate:  procedure OnCustomPoolTransactionBehavior(Sender: TDAConnectionManager; const Connection: IDAConnection)

---

Fires when unknown macro variable is found. it can be usable when user-defined variables are used inside sql or Dynamic Where expression.

property OnUnknownMacroVariable: TDAUnknownMacroVariableEvent read write
delegate:  procedure OnUnknownMacroVariable(Sender: TObject; const Name: string; var Value: string)