Database Binding

Learn how to connect TeeTree to databases and display hierarchical data from tables

TeeTree provides powerful database binding capabilities through the TDBTree component, allowing you to display hierarchical data directly from database tables.

Basic Database Connection

The simplest way to connect TeeTree to a database is using the TDBTree component:

type
  TDBTreeForm = class(TForm)
    DBTree1: TDBTree;
    Table1: TTable;
    Button1: TButton;
  end;

procedure TDBTreeForm.Button1Click(Sender: TObject);
begin
  // Open the table and refresh the tree
  Table1.Open;
  DBTree1.Refresh;
end;

Database Tree Wizard

TeeTree includes a visual wizard to configure database connections:

uses TreeDBEd;  // Database Tree Wizard dialog

procedure TDBTreeWizardForm.Button1Click(Sender: TObject);
begin
  ShowDBTreeEditor(Self, DBTree1);
end;

procedure TDBTreeWizardForm.CheckBox1Click(Sender: TObject);
begin
  Table1.Active := CheckBox1.Checked;
  
  DBTree1.Clear;
  DBTree1.Refresh;
end;

Master-Detail Relationships

Display complex hierarchical data with master-detail table relationships:

type
  TDBTreeMasterDetailForm = class(TForm)
    DBTree1: TDBTree;
    Customer: TTable;
    Orders: TTable;
    Items: TTable;
    DataSource1: TDataSource;
    DataSource2: TDataSource;
  end;

procedure TDBTreeMasterDetailForm.CheckBox1Click(Sender: TObject);
begin
  // Open or close all datasets
  Customer.Active := CheckBox1.Checked;
  Orders.Active := CheckBox1.Checked;
  Items.Active := CheckBox1.Checked;

  DBTree1.Clear;
  DBTree1.Refresh;
end;

// Customize node appearance when selected
procedure TDBTreeMasterDetailForm.DBTree1SelectShape(Sender: TTreeNodeShape);
begin
  // Make selected node bold
  with Sender.Font do
    Style := Style + [fsBold];
end;

procedure TDBTreeMasterDetailForm.DBTree1UnSelectShape(Sender: TTreeNodeShape);
begin
  // Remove bold when unselecting
  with Sender.Font do
    Style := Style - [fsBold];
end;

Formatting Database Nodes

Customize the appearance of database-bound nodes:

uses TreeShEd;

procedure TDBTreeFormatForm.CheckBox1Click(Sender: TObject);
begin
  Table1.Active := CheckBox1.Checked;
  
  DBTree1.Clear;
  DBTree1.Refresh;
end;

procedure TDBTreeFormatForm.Button2Click(Sender: TObject);
begin
  // Edit the layout format for database nodes
  EditTreeShape(Self, DBTree1.Layout[0].Format);
  DBTree1.Refresh;
end;

Grouping Database Records

Group database records by multiple fields:

procedure TDBTreeGroupForm.ComboFlat3Change(Sender: TObject);
begin
  // Set multiple parent fields for grouping
  with DBTree1.Layout[0] do
    ParentField := ComboFlat1.Items[ComboFlat1.ItemIndex] + ';' +
                   ComboFlat2.Items[ComboFlat2.ItemIndex] + ';' +
                   ComboFlat3.Items[ComboFlat3.ItemIndex];

  DBTree1.Refresh;
end;

Key Properties

Layout Configuration

The Layout property controls how database data is displayed:

• Layout[0].DataSet - The dataset to bind to
• Layout[0].TextField - Field to display as node text
• Layout[0].ParentField - Field(s) that define parent-child relationships
• Layout[0].Format - Visual formatting for nodes at this level

Multiple Levels

You can configure multiple layout levels for complex hierarchies:

// Configure first level
DBTree1.Layout[0].DataSet := CustomersTable;
DBTree1.Layout[0].TextField := 'CompanyName';

// Configure second level
DBTree1.Layout[1].DataSet := OrdersTable;
DBTree1.Layout[1].TextField := 'OrderNumber';
DBTree1.Layout[1].ParentField := 'CustomerID';

Best Practices

Performance Optimization

• Use BeginUpdate and EndUpdate when refreshing large datasets
• Close and reopen datasets when changing layout configuration
• Consider limiting the number of visible levels for very large hierarchies

Data Integrity

• Always call Clear before Refresh when dataset state changes
• Handle database connection errors gracefully
• Validate parent-child relationships in your data

User Experience

• Provide visual feedback during data loading
• Use the database wizard for initial setup
• Format nodes appropriately for the data type

Common Patterns

Self-Referencing Tables

For tables that reference themselves (like employee hierarchies):

DBTree1.Layout[0].DataSet := EmployeeTable;
DBTree1.Layout[0].TextField := 'EmployeeName';
DBTree1.Layout[0].ParentField := 'ManagerID';
DBTree1.Layout[0].IDField := 'EmployeeID';

Multiple Parent Fields

Group by multiple criteria using semicolon-separated field names:

DBTree1.Layout[0].ParentField := 'Department;Division;Region';

Related Topics

• Node Formatting - Style database nodes
• Events - Handle database tree events
• Layout Configuration - Advanced layout options