TDatabase class

In unit DB

Base class for connecting a FreePascal application to an external Database engine.

Declaration

pascal

TDatabase = class(TCustomConnection)

Inheritance

Descends from it: TSQLConnection

Description

TDatabase is a component whose purpose is to provide a connection to an external database engine, not to provide the database itself. This class provides generic methods for attachment to databases and querying their contents; the details of the actual connection are handled by database-specific components (such as SQLDb for SQL-based databases, or DBA for DBASE/FoxPro style databases).

Like TDataset, TDatabase is an abstract class. It provides methods to keep track of datasets connected to the database, and to close these datasets when the connection to the database is closed. To this end, it introduces a Connected boolean property, which indicates whether a connection to the database is established or not. The actual logic to establish a connection to a database must be implemented by descendent classes.

Properties

`TransactionCount`	public	Number of transaction components connected to this database.
`Transactions`	public	Indexed access to all transaction components connected to this database.
`Directory`	public	Directory for the database.
`IsSQLBased`	public	Is the database SQL based.
`Connected`	published	Is the database connected.
`DatabaseName`	published	Database name or path.
`KeepConnection`	published	Should the connection be kept active.
`Params`	published	Connection parameters.

Methods

`CheckConnected`	protected
`CheckDisConnected`	protected
`DoConnect`	protected
`DoDisconnect`	protected
`GetConnected`	protected
`GetDataset`	protected
`GetDataSetCount`	protected
`DoInternalConnect`	protected
`DoInternalDisConnect`	protected
`Create`	public	Initialize a new TDatabase class instance.
`Destroy`	public	Remove a TDatabase instance from memory.
`CloseDataSets`	public	Close all connected datasets.
`CloseTransactions`	public	End all transactions.
`StartTransaction`	public	Start a new transaction.
`EndTransaction`	public	End an active transaction.