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Get the Report →DataBind Controls to CSV Data in C++Builder
DataBind to CSV data in C++Builder with standard components and controls.
The CData ODBC Driver for CSV makes it easy to integrate connectivity to live CSV data with standard data access components in C++Builder. This article shows how to create a simple visual component library (VCL) application in C++Builder that connects to CSV data, executes queries, and displays the results in a grid. An additional section shows how to use FireDAC components to execute commands from code.
Create a Connection to CSV Data
If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs.
The DataSource property must be set to a valid local folder name.
Also, specify the IncludeFiles property to work with text files having extensions that differ from .csv, .tab, or .txt. Specify multiple file extensions in a comma-separated list. You can also set Extended Properties compatible with the Microsoft Jet OLE DB 4.0 driver. Alternatively, you can provide the format of text files in a Schema.ini file.
Set UseRowNumbers to true if you are deleting or updating in CSV. This will create a new column with the name RowNumber which will be used as key for that table.
You can then follow the steps below to use the Data Explorer to create a FireDAC connection to CSV.
- In a new VCL Forms application, expand the FireDAC node in the Data Explorer.
- Right-click the ODBC Data Source node in the Data Explorer.
- Click Add New Connection.
- Enter a name for the connection.
- In the FireDAC Connection Editor that appears, set the DataSource property to the name of the ODBC DSN for CSV.
Create VCL Applications with Connectivity to CSV Data
Follow the procedure below to start querying CSV data from a simple VCL application that displays the results of a query in a grid.
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Drop a TFDConnection component onto the form and set the following properties:
- ConnectionDefName: Select the FireDAC connection to CSV.
- Connected: Select True from the menu and, in the dialog that appears, enter your credentials.
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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 City, SUM(TotalDue) FROM Customer GROUP BY City
- Active: Set this property to true.
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.
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Drop a TDBGrid control onto the form and set the following property:
- DataSource: Select the name of the TDataSource.
- Drop a TFDGUIxWaitCursor onto the form — this is required to avoid a run-time error.
Execute Commands to CSV with FireDAC Components
You can use the TFDConnection and TFQuery components to execute queries to CSV data. This section provides CSV-specific examples of executing queries with the TFQuery component.
Connect to CSV 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 = "CData CSV ODBC Source";
FDConnection1->Connected = true;
To connect the TFDQuery component to CSV data, set the Connection property of the component. When a TFDQuery component is added at design time, its Connection property is automatically set to point to a TFDConnection on the form, as in the application above.
Create Parameterized Queries
To create a parameterized query, use the following syntax below:
FDQuery1->SQL->Text = "select * from Customer where firstname = :FirstName";
FDQuery1->ParamByName("firstname")->AsString = "Bob";
FDQuery1->Open();
The example above binds a string-type input parameter by name and then opens the dataset that results.
Prepare the Statement
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->SQL->Text = "select * from Customer where firstname = :FirstName";
FDQuery1->ParamByName("firstname")->AsString = "Bob";
FDQuery1->Open();
Related Articles
Below you can find other articles for using the CData ODBC Driver with RAD Studio, Delphi, and C++ Builder.