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DataBind Controls to MariaDB Data in Delphi XE7

DataBind to MariaDB data in Delphi with standard data access components and controls.

The CData ODBC Driver for MariaDB supports the ODBC standard to enable integration of live MariaDB data with visual form designers and other rapid development tools in Delphi XE7. The ODBC driver simplifies data access strategies for applications that share a single codebase like Delphi by providing a single API for database development. This article shows how to how to connect to MariaDB data and query data from a simple visual component library (VCL) application, as well as from Delphi code.

Create a FireDAC Connection to MariaDB Data

Follow the steps below to use the Data Explorer to create a FireDAC connection to MariaDB data.

  1. If you have not already, specify connection properties in a DSN (data source name). You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs.

    Below is a typical connection string:

    User=myUser;Password=myPassword;Database=NorthWind;Server=myServer;Port=3306;

    See the "Getting Started" chapter in the help documentation for a guide to setting the required properties in the Microsoft ODBC Data Source Administrator.

  2. In a new VCL Forms application, expand the FireDAC node in the Data Explorer.
  3. Right-click the ODBC Data Source node in the Data Explorer.
  4. Click Add New Connection.
  5. Enter a name for the connection.
  6. In the FireDAC Connection Editor that appears, set the DataSource property to the name of the ODBC DSN for MariaDB.

Create VCL Applications with Connectivity to MariaDB Data

Follow the procedure below to start executing queries to MariaDB data from a simple VCL application that displays the results of a query in a grid.

  1. Drop a TFDConnection component onto the form and set the following properties:

    • ConnectionDefName: Select the FireDAC connection to MariaDB data.
    • Connected: Select True from the menu and, in the dialog that appears, enter your credentials.
  2. Drop a TFDQuery component onto the form and set the properties below:

    • Connection: Set this property to the TFDConnection component, if this component is not already specified.
    • SQL: Click the button in the SQL property and enter a query. For example:

      SELECT * FROM Orders
    • Active: Set this property to true.
  3. Drop a TDataSource component onto the form and set the following property:

    • DataSet: In the menu for this property, select the name of the TFDQuery component.
  4. Drop a TDBGrid control onto the form and set the following property:

    • DataSource: Select the name of the TDataSource.
  5. Drop a TFDGUIxWaitCursor onto the form — this is required to avoid a run-time error.

Execute Commands to MariaDB with FireDAC Components

You can use the TFDConnection and TFQuery components to execute queries to MariaDB data. This section provides MariaDB data-specific examples of executing queries with the TFQuery component.

Connect to MariaDB Data

To connect to the data source, set the Connected property of the TFDConnection component to true. You can set the same properties from code:

FDConnection1.ConnectionDefName := 'mymariadb'; FDConnection1.Connected := true;

Create Parameterized Queries

Parameterized resources can improve performance: Preparing statements is costly in system resources and time. The connection must be active and open while a statement is prepared. By default, FireDAC prepares the query to avoid recompiling the same query over and over. To disable statement preparation, set ResourceOptions.DirectExecute to True; for example, when you need to execute a query only once.

Execute a Query

To execute a query that returns a result set, such as a select query, use the Open method. The Open method executes the query, returns the result set, and opens it. The Open method will return an error if the query does not produce a result set.

FDQuery1.Open('select * from Orders where ShipCountry = :ShipCountry',['USA']);

To execute a query that does not return a result set, such as a delete, use the ExecSQL method. The ExecSQL method will return an error if the query returns a result set. To retrieve the count of affected rows for an insert, update, or delete, use the TFD.RowsAffected property.

FDQuery1.ExecSQL('delete from Orders where Id= :myId',['x12345']); i := FDQuery1.RowsAffected;
 
 
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