Class TDAODatabase (unit DAODatabase)

Inherits from

TComponent

TDAODatabase provides control over a connection to single database in a database application.
Use TDAODatabase when a database application requires any of the following control over a database connection:

  1. Persistent database connections
  2. Customized database logins
  3. Transaction control

Note

You may use original DAO Database and Workspace objects through _Database and _Workspace interfaces, which are declared in public section of TDAODatabase.

Functions

procedure BeginTrans;

Opens new transaction.

procedure Close;

Closes a dataset.

Call Close to set the Active property of a dataset to False. When Active is False, the dataset is closed; the dataset cannot read data from or write data to the database.

procedure CommitTrans;

CommitTrans finishes current transaction and keeps changes.

procedure Execute(SQL: string);

Executes the SQL statement.

Call Execute to execute the INSERT, UPDATE, or DELETE statement without parameters.

procedure GetQueryDefNames(List: TStrings);

Populates a string list with the names of QueryDefs associated with a specified database.

procedure GetTableIndexes(TableName: string; List: TStrings);

Populates a string list with the names of Indexes associated with a specified table.

procedure GetTableNames(List: TStrings);

Populates a string list with the names of TableDefs associated with a specified database.

procedure Open;

Connects to a database.

Call Open to establish a connection to a database, specified by the DatabaseName property.
Setting Connected to True also connects to the database.

procedure Rollback;

Cancels all changes for the current transaction and ends the transaction.

Properties

property Connected : Boolean

Indicates whether or not a database connection is active.

Set Connected to True to establish a database connection without opening a dataset.
Set Connected to False to close a database connection. An application can check Connected to determine the current status of a database connection.

property CreateWorkspace : Boolean

Set CreateWorkspace to True when you need to create Workspace object.
Workspace is necessary for work with Access user security.

property DatabaseName : string

Expression specifying a name of an existing file of a database.

property Exclusive : Boolean

Defines a type of access to a database.

Set Exclusive to True to define an exclusive access to a database.
Set Exclusive to False for common access.

property Password : string

Use Password to specify password of the protected database.

Note

It is the password of a database, instead of user.

property ReadOnly : Boolean

Set ReadOnly to True if the database opens only for reading.

property Workspace : TWorkspace

Workspace provides properties, which are necessary for work with secured databases.

property Datasets : TList

Provides an indexed array of all active datasets for a database component.

Use DataSets to access active datasets associated with a database component. An active dataset is one that is currently open.

property RecordsAffected : Integer

Returns number of records, which were used by last call of a method Execute.

The returned value lays in an interval from 0 up to number of records, which were used by last call of method Execute for TDAODatabase.

Variables

_Database : Database;

Provides interface to native DAO Database object.

_Workspace : Workspace;

Provides interface to native DAO Workspace object.

Note

You may use interface to Workspace only when CreateWorkspace is True.