List boxes: List box controls help to show the list of items which enables the user to choose an item from the list. The user may choose one of the items from the list, causing the item to appear selected at runtime. The selected items will be displayed on ListBox control. Get the items from ListBox control: The item which is selected by user from ListBox is stored into ListBox’s SelectedItem property. Steps to determine the selected item in Listbox: If anyone tries to get the value when ListBox’s SelectedItem is empty, then it will occur with an exception. Always ensure that item is selected before reading an item in the SelectedItem. The items stored in ListBox with index value. This is done by “SelectedIndex” property. The item index is stored into SelectedIndex property. The index is a number to determine the position of Items in ListBox. If first item means index value is “0”, second means “1”, and so on. If there is no item in ListBox, then the index value is set to “-1”. The following example code checks whether the SelectedIndex property is “-1” or not. if(courseListBox.SelectionIndex != -1) { selectedProduct = productListBox.SelectedItem.ToString(); }

Question

A company database needs to store information about employees (identified by SIN, with salary and phone as attributes), departments (identified by DID, with dname and budget as attributes), and children of employees (with name and age as attributes). Employees work in departments; each department is managed by an employee; a child must be identified uniquely by name when the parent (who is an employee; assume that only one parent works for the company) is known. We are not interested in information about a child once the parent leaves the company. Draw an ER diagram using Crows Foot notation that captures this information. Important: Must submit both ER Diagram and Relational Schema images in your solution here.

Answer 1

Question

Chapter 4, Problem 9AW

Program Plan Intro

List boxes:

List box controls help to show the list of items which enables the user to choose an item from the list.

The user may choose one of the items from the list, causing the item to appear selected at runtime.

The selected items will be displayed on ListBox control.

Get the items from ListBox control:

The item which is selected by user from ListBox is stored into ListBox’s SelectedItem property.

Steps to determine the selected item in Listbox:

If anyone tries to get the value when ListBox’s SelectedItem is empty, then it will occur with an exception.

Always ensure that item is selected before reading an item in the SelectedItem. The items stored in ListBox with index value.

This is done by “SelectedIndex” property.

The item index is stored into SelectedIndex property.

The index is a number to determine the position of Items in ListBox.

If first item means index value is “0”, second means “1”, and so on. If there is no item in ListBox, then the index value is set to “-1”.

The following example code checks whether the SelectedIndex property is “-1” or not.

if(courseListBox.SelectionIndex != -1)

{

selectedProduct = productListBox.SelectedItem.ToString();

}

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