Introducing Delphi Programming Theory through Practice

by Barrow, John; Miller, Linda; Malan, Katherine; Gelderblom, Helene

• ISBN13: 9780195789119
• ISBN10: 0195789113
• Edition: 4th
• Format: Paperback
• Copyright: 2005-07-28
• Publisher: Oxford University Press

Summary

The fourth edition of Introducing Delphi Programming builds on the strengths of the previous editions to provide an even better introduction to computer programming.

Author Biography

John Barrow is a Professor in the School of Computing at Unisa Linda Miller is a Senior Lecturer in the School of Computing at Unisa Katherine Malan is a Lecturer in Computing Education at CIMSTE (Centre for the Improvement of Mathematics, Science and Technology Education), Unisa Helene Gelderblom is a Senior Lecturer in the School of Computing at Unisa

Table of Contents

Preface	v
Introduction to visual programming	1	(24)
Purpose of this Chapter
Delphi's Integrated Development Environment	2	(3)
The Form Designer	3	(1)
The Object Inspector	3	(1)
Properties	4	(1)
The Component palette or Tool palette	4	(1)
The Object TreeView or Model View	5	(1)
Example 1.1 A simple program	5	(6)
Writing a program statement	6	(1)
The Speed bar	6	(1)
Running the program	7	(1)
Exiting the program	7	(1)
An event handler	8	(1)
Setting a property in the Object Inspector and in the program	9	(1)
Naming and saving projects	10	(1)
Example 1.2 Dealing with errors	11	(1)
Making more errors	11	(1)
Diagnosing errors	12	(1)
Example 1.3 Another button, another colour	12	(7)
Ex 1.3 Step 1 Adding another button	14	(1)
Ex 1.3 Step 2 More program statements	15	(1)
Understanding event driven programming	16	(1)
Ex 1.3 Step 3 Enabling and disabling buttons	16	(1)
Making life easier for the user	17	(1)
Ex 1.3 Step 4 Accelerator (or hot) keys	18	(1)
The interaction between the Form Designer, the Object Inspector, and the Object TreeView or Model View	18	(1)
A note for experienced programmers	18	(1)
Review	19	(1)
Important Concepts	19	(2)
New Delphi Features	21	(1)
Problems	22	(3)
Programming with visual components	25	(22)
Purpose of this Chapter
Example 2.1 Simple text output	26	(2)
Example 2.2 Reading text in from the user	28	(2)
Assignment statement	29	(1)
Reading in text from the keyboard	30	(1)
Example 2.3 The `Close' bitmap button	30	(1)
Example 2.4 Setting focus and clearing text	31	(2)
Economy: Making life easier for the user	32	(1)
Method calls	32	(1)
Selecting components on a form	32	(1)
Example 2.5 Positioning and sizing components	33	(1)
Example 2.6 GroupBox and RadioButton components	34	(2)
Selecting multiple components	35	(1)
Example 2.7 Setting form colours with RadioButtons	36	(3)
When to use RadioButtons	38	(1)
Example 2.8 Two groups of RadioButtons	39	(2)
Listing valid methods and properties through Code Completion	40	(1)
A comment on the examples in this chapter	41	(1)
Review	41	(1)
Important Concepts	41	(2)
New Delphi Features	43	(2)
Problems	45	(2)
String variables	47	(19)
Purpose of this Chapter
The notion of a variable	48	(1)
Example 3.1 Text input and output using a variable	48	(2)
Programming instructions versus program comments	49	(1)
Associating values with variable names	49	(1)
The type part of a variable declaration	50	(1)
Example 3.2 What happens if we don't declare a variable?	50	(1)
Undeclared identifiers	50	(1)
Example 3.3 Experimenting with incompatible types	51	(1)
The name part of a variable declaration	51	(1)
Example 3.4 Trying out a few names for components	52	(1)
Character strings	53	(1)
Example 3.5 Using string variables and a ListBox	53	(3)
String variables	55	(1)
The ListBox component	55	(1)
String concatenation	55	(1)
Example 3.6 A program using string concatenation	56	(3)
Ex 3.6 Step 1 Creating the screen layout	57	(1)
Ex 3.6 Step 2 The variables	57	(1)
Ex 3.6 Step 3 Doing the concatenation	58	(1)
Ex 3.6 Step 4 Adding the couple to the ListBox	58	(1)
The number of variables used	59	(1)
Variable scope: subroutine level and unit level	59	(1)
Example 3.7 When is a variable necessary?	59	(3)
Ex 3.7 Step 1 Creating the screen layout	60	(1)
Ex 3.7 Step 2 First attempt at the event handler	60	(1)
Ex 3.7 Step 3 Second attempt at at the event handler using a variable	61	(1)
Review	62	(1)
Important Concepts	62	(1)
New Delphi Features	63	(1)
Problems	63	(3)
Using numbers	66	(32)
Purpose of this Chapter
Example 4.1 A simple calculator (integer addition)	67	(5)
Finding the SpinEdit component	67	(1)
Consistent user interfaces	68	(1)
Ex 4.1 Adding the numbers	68	(1)
Declaring an integer	68	(1)
The SpinEdit component	68	(1)
Assignment and arithmetic expressions	69	(1)
Converting an integer to a string	70	(1)
Numbers in strings	71	(1)
Integer arithmetic	71	(1)
Integer division: MOD and DIV	71	(1)
SpinEdit and Samples tab	72	(1)
Example 4.2 Extended calculator (integer arithmetic)	72	(7)
Ex 4.2 Step 1 Creating the screen layout	73	(1)
Ex 4.2 Step 2 Doing the arithmetic	74	(1)
Ex 4.2 Step 3 The remaining four operator buttons	75	(1)
Why do we declare Answer in each event handler?	76	(1)
Ex 4.2 Step 4 Resetting values	76	(1)
Floating point (real) numbers	76	(1)
Run-time errors	77	(1)
Disabling debugger exception handling	78	(1)
Typing a real number into a SpinEdit	79	(1)
Example 4.3 Rand to Euro calculator (version 1)	79	(5)
Floating point (real) data types	80	(1)
Converting a real number to a string with FloatToStrF	81	(1)
More examples of FloatToStrF conversions	82	(1)
FloatToStrF versus FloatToStr	82	(1)
Using a constant for the exchange rate	83	(1)
Constants	84	(1)
Example 4.4 Rand to Euro calculator (version 2)	84	(8)
Ex 4.4 Step 1 Creating the screen layout	85	(1)
Giving the user hints	86	(1)
Ex 4.4 Step 2 Using constants	87	(1)
Ex 4.4 Step 3 The variables needed	87	(1)
Ex 4.4 Step 4 Converting the user's input to a floating-point number	87	(1)
Ex 4.4 Step 5 Doing the calculation	87	(1)
Real division	88	(1)
Operator precedence	88	(1)
Data type of the result of an expression	89	(1)
Ex 4.4 Step 6 Displaying the answer	90	(1)
Ex 4.4 Step 7 Clearing values	90	(1)
Both conversion event handlers	90	(1)
Attempting to convert alphabetical characters to a number	91	(1)
Review	92	(1)
Important Concepts	92	(1)
New Delphi Features	93	(1)
Problems	94	(4)
Conditional execution	98	(29)
Purpose of this Chapter
Boolean expressions	99	(1)
Example 5.1 Boolean expressions	99	(4)
The if...then...else statements	102	(1)
The difference between = and :=	102	(1)
Comparing strings	103	(1)
Example 5.2 Comparing strings	103	(3)
Ignoring the case when comparing strings	104	(1)
The if...then...else statement	105	(1)
Logical operators in Boolean expressions	105	(1)
Example 5.3 Ifs, logical operators and Boolean variables	106	(4)
Boolean variables	107	(1)
Component properties in Boolean expressions	107	(1)
Ex 5.3 Working through the program code	108	(1)
Evaluating case 1: Step 1	108	(1)
Evaluating case 1: Step 2	108	(1)
Evaluating case 1: Step 3	109	(1)
Important comment	109	(1)
Order of precedence	109	(1)
Example 5.4 Compound statements	110	(4)
Structuring an if...then...else statement	112	(1)
Semicolons in if...then...else statements	112	(1)
Common Windows dialogs in Delphi	113	(1)
Example 5.5 Windows common dialogs	114	(8)
Ex 5.5 Step 1 Create the form	114	(1)
Visual versus non-visual components	115	(1)
Ex 5.5 Step 2 Loading text from a file	115	(2)
The Execute method	117	(1)
Ex 5.5 Step 3 Opening a file that doesn't exist	117	(1)
Ex 5.5 Step 4 Exception handling	118	(1)
The try...except statement	119	(1)
Ex 5.5 Step 5 Saving text to a file	119	(1)
Ex 5.5 Step 6 Exception handling in the Save text event handler	120	(1)
Ex 5.5 Step 7 Changing the Memo's font	120	(1)
Loading and saving text in Memos and ListBoxes	121	(1)
Review	122	(1)
Important Concepts	122	(1)
New Delphi Features	123	(2)
Problems	125	(2)
Nested and multiple conditions	127	(37)
Purpose of this Chapter
Example 6.1 A nested If statement	128	(2)
The layout of nested If statements	128	(2)
Example 6.2 Calculating commission on sales	130	(5)
A first attempt	131	(1)
Ex 6.2 Step 1 Creating the form	132	(1)
Ex 6.2 Step 2 Converting the input to a real value	132	(1)
Ex 6.2 Step 3 A nested If statement	132	(2)
The order of conditions	134	(1)
Ex 6.2 Step 4 Displaying the output	134	(1)
Ex 6.2 Step 5 Creating the event handler	135	(1)
Example 6.3 Improving nested Ifs	135	(4)
The CheckBox component	136	(1)
A better solution	137	(1)
Further improvement	137	(1)
The Case statement	138	(1)
Example 6.4 A bursary scheme	139	(5)
Ex 6.4 Step 1 Creating the form	140	(1)
Ex 6.4 Step 2 A simplified version using a Case statement	140	(1)
Ex 6.4 Step 3 Including the subject requirements	141	(1)
The structure of a Case statement	142	(1)
When is a Case statement preferable to an If statement?	143	(1)
Ex 6.4 Step 4 Using RadioButtons to get the score	143	(1)
Example 6.5 Generating words from characters	144	(2)
The relationship between characters and strings	144	(1)
Ex 6.5 Step 1 Creating the form	145	(1)
Ex 6.5 Step 2 Writing the event handler	146	(1)
Example 6.6 Classifying names with a Case statement	146	(3)
Input dialog boxes	147	(1)
String processing	148	(1)
Example 6.7 String manipulation	149	(4)
Ex 6.7 Step 1 The event handlers	150	(1)
The Memo's Text property	151	(1)
Ex 6.7 Step 2 Finding a substring in a string	151	(1)
Ex 6.7 Step 3 Deleting a substring from a string	151	(1)
Ex 6.7 Step 4 Inserting a substring into a string	152	(1)
Copying part of a string	152	(1)
Example 6.8 Message dialog boxes	153	(4)
Dialog box examples	153	(2)
Ex 6.8 Handling exceptions using message dialogs	155	(2)
Review	157	(1)
Important Concepts	157	(1)
New Delphi Features	158	(3)
Problems	161	(3)
Repetition	164	(28)
Purpose of this Chapter
Example 7.1 A For loop	165	(6)
Ex 7.1 Step 1 Creating the form	165	(1)
Ex 7.1 Step 2 Calculating the sum	166	(1)
Trace tables	166	(1)
Initializing variables	167	(1)
The For loop	168	(1)
Counting downwards with For	169	(1)
Compound statements with For	169	(1)
Changing the upper bound inside the loop	170	(1)
Example 7.2 A raffle competition	171	(5)
The Random function	171	(1)
Ex 7.2 Step 1 The user interface	172	(1)
Ex 7.2 Step 2 The For statement	172	(1)
Ex 7.2 Step 3 The loop's body	173	(1)
Ex 7.2 Step 4 The complete For loop	173	(1)
Ex 7.2 Step 5 The event handler	174	(1)
The Randomize procedure	174	(1)
Commenting code effectively	175	(1)
Example 7.3 Nested For loops	176	(1)
The While...do statement	176	(1)
Example 7.4 A While...do statement	177	(1)
Two important rules	177	(1)
Example 7.5 Finding a name in a Memo	178	(6)
Ex 7.5 Step 1 Creating the form	179	(1)
Ex 7.5 Step 2 Saving names to and loading names from a file on disk	179	(1)
Ex 7.5 Step 3 Finding the name	180	(1)
Numbering and counting the lines in a Memo	181	(1)
Problems with the solution	181	(1)
Ex 7.5 Step 4 An improved version of the event handler	182	(1)
Ex 7.5 Step 5 Resetting the input fields	183	(1)
Choosing between For and While	184	(1)
Example 7.6 Nested loops	184	(3)
The loops	184	(1)
Ex 7.6 Step 1 The body of the outer loop	185	(1)
Ex 7.6 Step 2 The program	185	(2)
The Repeat...until loop	187	(1)
Review	187	(1)
Important Concepts	188	(1)
New Delphi Features	188	(1)
Problems	189	(3)
Arrays and indexes	192	(39)
Purpose of this Chapter
Strings and indexes	193	(1)
Example 8.1 Reversing a string	193	(2)
Ex 8.1 Step 1 Creating the form	193	(1)
Arrays	194	(1)
Example 8.2 Reversing five strings	195	(5)
Ex 8.2 Step 1 Creating the form	196	(1)
Ex 8.2 Step 2 Creating the event handler	197	(1)
Looping through an array	198	(1)
Ex 8.2 Step 3 Programming the second button	198	(1)
Scope and unit-level declarations	199	(1)
Ex 8.2 Step 4 Declaring array Words as a unit-level variable	199	(1)
Dynamic arrays	200	(1)
Example 8.3 Test results	200	(6)
Ex 8.3 Step 1 Creating the form	202	(1)
Ex 8.3 Step 2 Creating the event handler	202	(2)
Initialising arrays and array constants	204	(1)
Two-dimensional arrays	205	(1)
The ComboBox component	205	(1)
Example 8.4 ComboBoxes and two-dimensional arrays	206	(3)
Ex 8.4 Step 1 Create the form	206	(1)
Ex 8.4 Step 2 Defining the array constants	207	(1)
Ex 8.4 Step 3 Loading the ComboBoxes with values	208	(1)
The ItemIndex property	208	(1)
Ex 8.4 Step 4 Showing the distances	209	(1)
Example 8.5 ListBoxes	209	(5)
Ex 8.5 Step 1 The interface	210	(1)
Ex 8.5 Step 2 Deleting names from the list	211	(1)
The Delete method	212	(1)
Initialization of variables	212	(1)
Ex 8.5 Step 3 A problem with the solution	213	(1)
RadioGroups	213	(1)
Example 8.6 Using a RadioGroup	214	(4)
Ex 8.6 Step 1 Open the project	215	(1)
Ex 8.6 Step 2 The interface	215	(1)
Ex 8.6 Step 3 The code	216	(1)
Using a Case statement with the RadioGroup	217	(1)
An alternative solution	217	(1)
Example 8.7 Sixpence Joe (a short version)	218	(7)
Ex 8.7 Step 1 Open the Sixpence Joe program	218	(1)
Ex 8.7 Step 2 Remove the event handlers from the program	218	(1)
Ex 8.7 Step 3 The RadioGroup	218	(1)
Ex 8.7 Step 4 The RadioGroup's event handler	219	(1)
Example 8.8 The Controls and ControlCount properties	219	(1)
Ex 8.8 Step 1 Creating the interface	220	(1)
Ex 8.8 Step 2 Resetting the components	221	(1)
The Controls and ControlCount properties	222	(1)
Typecasting	222	(1)
Unchecking the CheckBoxes	223	(1)
The Components and ComponentCount properties	223	(2)
Review	225	(1)
Important Concepts	225	(1)
New Delphi Features	226	(2)
Problems	228	(3)
Menus and actions	231	(31)
Purpose of this Chapter
Menus	232	(1)
Example 9.1 Drop-down, cascading and pop-up menus	232	(13)
Ex 9.1 Step 1 Adding a menu to the form	233	(2)
Ex 9.1 Step 2 Associating events and shortcuts with the MenuItems	235	(1)
Shortcuts versus accelerator keys	236	(1)
Editing a menu	236	(1)
Ex 9.1 Step 3 Adding a main MenuItem	237	(1)
Ex 9.1 Step 4 Adding an item to a drop-down menu	237	(1)
The ColorDialog component	238	(1)
Ex 9.1 Step 5 Adding a cascading submenu	239	(1)
Cascading submenus	239	(1)
Ex 9.1 Step 6 Changing the font using checkmarked menu items	240	(1)
Checking and unchecking menu items	240	(1)
Sets	241	(2)
Ex 9.1 Step 7 Adding a pop-up menu	243	(1)
Ex 9.1 Step 8 Associating events with the pop-up menu items	244	(1)
Using existing event handlers	244	(1)
Example 9.2 Action lists	245	(11)
Ex 9.2 Step 1 Creating the form	246	(1)
Ex 9.2 Step 2 Creating an Action list	247	(3)
Ex 9.2 Step 3 Linking buttons to the Actions	250	(1)
Action properties	250	(1)
Ex 9.2 Step 4 Adding a main menu	250	(2)
Ex 9.2 Step 5 Creating shortcuts for all the menu items	252	(1)
Ex 9.2 Step 6 Adding a pop-up menu	253	(1)
Ex 9.2 Step 7 Enabling/disabling the Actions	253	(2)
When different sources trigger the same operation	255	(1)
Review	256	(1)
Important Concepts	256	(1)
New Delphi Features	257	(2)
Problems	259	(3)
Events and parameters	262	(19)
Purpose of this Chapter
Event-driven programming	263	(1)
Example 10.1 OnMouseMove event handlers	263	(3)
Accessing context-sensitive online Help	264	(1)
Writing the event handlers	264	(2)
User events and system events	266	(1)
Example 10.2 Generating system events through the Timer	266	(2)
Visual and non-visual components	267	(1)
The Timer	267	(1)
Example 10.3 Combining system and user events	268	(3)
Ex 10.3 Step 1 Enabling the Timer programmatically	269	(1)
Ex 10.3 Step 2 Routing events	270	(1)
Ex 10.3 Step 3 Renaming event handlers	270	(1)
Ex 10.3 Step 4 Some final touches	270	(1)
Example 10.4 The `form' system events	271	(1)
Example 10.5 Parameters in event handlers	271	(2)
Ex 10.5 Step 1 Positioning squares	273	(1)
Example 10.6 Help for the OnMouseDown event parameters	273	(1)
Example 10.7 Detecting the left mouse button	274	(1)
Review	275	(1)
Important Concepts	275	(1)
New Delphi Features	276	(1)
Problems	277	(4)
Methods and parameters	281	(11)
Purpose of this Chapter
Example 11.1 Methods and the Memo component	282	(2)
Example 11.2 Methods with constants as parameters	284	(2)
Ex 11.2 Step 1 The meaning of the parameters	285	(1)
Ex 11.2 Step 2 Test the program	286	(1)
Example 11.3 The order of parameters	286	(1)
Changing parameter order	286	(1)
Example 11.4 Wrong type or number of parameters	287	(2)
Specifying a method call	288	(1)
Review	289	(1)
Important Concepts	289	(1)
New Delphi Features	290	(1)
Problems	291	(1)
Procedures and parameters	292	(43)
Purpose of this Chapter
Declaring and defining a method	293	(1)
Example 12.1 Procedures and Sixpence Joe	294	(4)
Calling (invoking) a procedure	296	(1)
The structure of a simple procedure	296	(1)
Reasons for using procedures	297	(1)
General comments on procedures	297	(1)
Example 12.2 Parameter list matching	298	(1)
Example 12.3 Parameter names	299	(1)
Example 12.4 Declare the method in the type declaration	299	(1)
Example 12.5 Variables as parameters	300	(1)
Example 12.6 A method is part of a class	301	(1)
Example 12.7 Components as parameters	301	(6)
Ex 12.7 Step 1 The program without procedures	301	(2)
Ex 12.7 Step 2 Introducing a simple method	303	(2)
Ex 12.7 Step 3 Passing a component as a parameter	305	(1)
Why and when should we use procedures?	306	(1)
Commenting a method	307	(1)
Example 12.8 Returning values from a procedure	307	(4)
Ex 12.8 Step 1 The Inc(x) procedure	307	(1)
Ex 12.8 Step 2 A var parameter	308	(1)
The method CalcFee	309	(1)
Returning to the event handler: using the variable parameter's value	310	(1)
Error: leaving out the `var'	310	(1)
Hiding detail with a method	311	(1)
Example 12.9 Sixpence Joe's selling price calculator	311	(9)
User interface	311	(1)
Incremental development	312	(1)
Ex 12.9 Step 1 The user interface	313	(2)
Ex 12.9 Step 2 Calculating 15% markup directly	315	(1)
Ex 12.9 Step 3 Creating procedure methods	316	(1)
Ex 12.9 Step 4 Adding further event handlers	317	(1)
Ex 12.9 Step 5 Testing the program	318	(1)
Ex 12.9 Step 6 Some refinements	318	(2)
Example 12.10 Variable parameters in event handlers	320	(2)
Delphi's event signatures	321	(1)
User interface factors: reversibility vs economy	321	(1)
Delphi's other parameter types	322	(1)
Review	322	(1)
Important Concepts	323	(4)
New Delphi Features	327	(1)
Problems	327	(8)
Functions and exceptions	335	(30)
Purpose of this Chapter
Delphi's standard functions	336	(1)
Example 13.1 A simple function	336	(4)
Ex 13.1 Step 1 Run and test the program	338	(1)
Ex 13.1 Step 2 How do we write a function?	338	(1)
Ex 13.1 Step 3 Supplying the function's value to the calling statement	339	(1)
Ex 13.1 Step 4 How do we use a function?	340	(1)
Ex 13.1 Step 5 Displaying the output	340	(1)
Ex 13.1 Step 6 Soft click	340	(1)
Example 13.2 Joe's Security Emporium	340	(6)
Ex 13.2 Step 1 The program operation	343	(2)
Ex 13.2 Step 2 Procedures or functions?	345	(1)
Ex 13.2 Step 3 Enhancing the If statements	345	(1)
Example 13.3 Henry's `Horse Heaven' Farm	346	(5)
Ex 13.3 Step 1 Changes to the form	347	(1)
Ex 13.3 Step 2 Changing the code	347	(2)
Ex 13.3 Step 3 Comments on each subroutine	349	(1)
Ex 13.3 Step 4 Alternative implementations	350	(1)
Differences between functions and procedures	350	(1)
Example 13.4 Nested function calls	351	(1)
Example 13.5 Exception handling	352	(5)
Ex 13.5 Step 1 Accepting three characters only	353	(1)
Ex 13.5 Step 2 Generating an Invalid Status	354	(1)
Ex 13.5 Step 3 The try...finally construct	355	(1)
Ex 13.5 Step 4 Handling the exceptions closer to the source	356	(1)
Review	357	(1)
Important Concepts	358	(2)
New Delphi Features	360	(1)
Problems	361	(4)
Debugging and testing	365	(18)
Purpose of this Chapter
Preliminary	366	(1)
Example 14.1 Breakpoints and tracing	367	(3)
Ex 14.1 Step 1 btnParSec's OnClick handler	367	(1)
Ex 14.1 Step 2 Setting breakpoints	368	(2)
Example 14.2 Method calls and watches	370	(10)
Ex 14.2 Step 1 Introducing a method	370	(1)
Ex 14.2 Step 2 Tracing flow to a method and back	371	(1)
Ex 14.2 Step 3 Setting the Watch List	372	(1)
Ex 14.2 Step 4 Tracing into, stepping over, and other niceties	373	(1)
Ex 14.2 Step 5 Value and variable parameters	373	(2)
Ex 14.2 Step 6 Parameter order	375	(1)
Additional Debug features	376	(1)
Types of error	376	(2)
Testing	378	(2)
Review	380	(1)
Important Concepts	381	(1)
New Delphi Features	382	(1)
Problems	382	(1)
Introduction to database programming	383	(31)
Purpose of this Chapter
What is a database?	384	(1)
Delphi's alternatives in terms of data access	384	(1)
MySQL database	385	(1)
A library database application	385	(1)
Example 15.1 Create the database containing one table	386	(5)
Ex 15.1 Step 1 Make sure the MySQL server is running	387	(1)
Ex 15.1 Step 2 Connecting to the database server	387	(1)
Ex 15.1 Step 3 Create the database	388	(1)
Ex 15.1 Step 4 Create table LibraryMember	389	(1)
What is a key?	390	(1)
Ex 15.1 Step 5 Change the structure of the table	391	(1)
Handling database errors	391	(1)
Example 15.2 Create an application that uses the table through a DBGrid component	391	(10)
Ex 15.2 Step 1 Build the connection to the database	391	(2)
Ex 15.2 Step 2 Add the dbExpress and DataAccess components	393	(1)
Ex 15.2 Step 3 Add the data control components	393	(1)
Ex 15.2 Step 4 Specify the display lengths of the data in the DBGrid	394	(1)
Ex 15.2 Step 5 Run the application	394	(1)
A local (unidirectional) data set	395	(1)
Bringing the database and the application together	396	(1)
The SQLConnection component	397	(1)
The SQLDataSet component	397	(1)
The DataSetProvider component	397	(1)
The ClientDataSet component	398	(1)
The DataSource component	398	(1)
The data control component: DBGrid	398	(1)
Ex 15.2 Step 6 Apply the updates to the database	399	(1)
The ClientDataSet's ChangeCount property	399	(1)
The ClientDataSet's ApplyUpdates method	399	(1)
Ex 15.2 Step 7 Undo data updates	399	(1)
The ClientDataSet's UndoLastChange method	400	(1)
Opening and closing data sets correctly	400	(1)
Ex 15.2 Step 8 Open the ClientDataSet when the form is displayed	400	(1)
Example 15.3 Creating the book data table and using it in an application	401	(5)
Ex 15.3 Step 1 Create the LibraryBook table in database MyVPLibrary	401	(1)
Creating an application to add data to the LibraryBook table in database MyVPLibrary	401	(1)
Ex 15.3 Step 2 Build the connection to the database	402	(1)
Ex 15.3 Step 3 Add the dbExpress and DataAccess components	402	(1)
Ex 15.3 Step 4 Add the DBEdit Data Control components	403	(1)
Ex 15.3 Step 5 Write the event handlers	404	(1)
Ex 15.3 Step 6 Run the application	404	(1)
The current record	405	(1)
The DBEdit data control	405	(1)
DBNavigator data control	405	(1)
Example 15.4 Change example 15.3 to use a DBComboBox	406	(2)
The DBComboBox	407	(1)
When the primary key consists of more than one field: The SQLDataSet component	407	(1)
Review	408	(1)
Important Concepts	408	(1)
New Delphi Features	409	(3)
Problems	412	(2)
Database programming using data modules and multiple forms	414	(40)
Purpose of this Chapter
Example 16.1 Database maintenance | Member table... and Book table...	415	(10)
Ex 16.1 Step 1 Create the main form of the application	416	(1)
Ex 16.1 Step 2 Add the Member and Book forms to the project	417	(1)
Multiple forms and units in an application	417	(1)
The Project Options	418	(1)
Ex 16.1 Step 3 Add code to activate frmMember from the main form	418	(1)
Ex 16.1 Step 4 Make unit Memberu accessible from the main form	419	(1)
Ex 16.1 Step 5 Adding code to activate frmBook from the main form	419	(1)
Ex 16.1 Step 6 Running the application without making unit Booku accessible to the main form	419	(1)
Showing forms: modal and modeless	420	(1)
User interface factors: modal vs modeless	420	(1)
Using a data module	421	(1)
Ex 16.1 Step 7 Create a data module for the Data Access and dbExpress components	421	(1)
Ex 16.1 Step 8 Move the dbExpress and Data Access components from frmMember to the data module	422	(1)
Ex 16.1 Step 9 Linking to the data module	422	(1)
Ex 16.1 Step 10 Access the data module from frmMember's event handlers	423	(1)
Ex 16.1 Step 11 Modify frmBook to use the data module	424	(1)
Ex 16.1 Step 12 Linking the DBEdits on frmBook to the data module	424	(1)
Ex 16.1 Step 13 Accessing the data module from frmBook's event handlers	424	(1)
Example 16.2 Library acquisitions: using an SQL statement and adding records programmatically	425	(10)
Ex 16.2 Step 1 Create table LibraryAcquisition in database MyVPLibrary	426	(1)
Ex 16.2 Step 2 Add the dbExpress and Data Access components for LibraryAcquisition to the data module	427	(1)
Ex 16.2 Step 3 Create the new form and activate it from the main form	427	(2)
The DBLookupComboBox component	429	(1)
The DBText component	429	(1)
Ex 16.2 Step 4 Create event handlers FormClose, UndoLastChange and FormShow	429	(1)
SQL's SELECT statement	430	(1)
The SQL query in TfrmAcquisition.FormShow	431	(1)
Ex 16.2 Step 5 Refreshing the ClientDataSet for the books	432	(1)
The ClientDataSet's Refresh method	432	(1)
Ex 16.2 Step 6 Using DateUtils	432	(1)
Ex 16.2 Step 7 The Generate new acquisition number event handler	433	(1)
Date operations	433	(1)
Working with the ClientDataSet	434	(1)
Example 16.3 Library loans | Issue book	435	(7)
Clicking the Issue book... menu item	435	(1)
Ex 16.3 Step 1 Create the LibraryLoan table	436	(1)
Ex 16.3 Step 2 Add LibraryLoan to the data module	436	(1)
What happens when a book is issued	436	(1)
Ex 16.3 Step 3 Creating the form for issuing a book	437	(2)
Ex 16.3 Step 4 Make unit IssueBooku accessible from C16e01u	439	(1)
Ex 16.3 Step 5 The event handlers for frmIssueBook	439	(2)
Searching for a specific record using the FindKey method	441	(1)
Date routines	441	(1)
Getting values from and entering values into the fields of the new record	441	(1)
Example 16.4 Returning or renewing a book	442	(5)
Ex 16.4 Step 1 Create the Return / Renew book form	442	(1)
Ex 16.4 Step 2 Displaying the form from the main menu	443	(1)
Ex 16.4 Step 3 The event handlers and method	443	(2)
The ClientDataSet's FindNearest method	445	(1)
The application now	446	(1)
Exception handling	446	(1)
The DateTimePicker component	446	(1)
Review	447	(1)
INew Delphi Features	447	(3)
Problems	450	(4)
Reporting: using Rave reports	454	(32)
Purpose of this Chapter
Rave reports	455	(1)
Example 17.1 Introducing Rave: printing/viewing late return notices	455	(10)
Ex 17.1 Step 1 Change the due dates in some records for testing purposes	456	(1)
Ex 17.1 Step 2 TrvProject and TrvSystem components	456	(1)
The RvProject and RvSystem components	456	(1)
Ex 17.1 Step 3 The Rave Visual Designer	456	(1)
The Project TreeView	457	(1)
Ex 17.1 Step 4 Executing the report from the application	458	(1)
Ex 17.1 Step 5 Interact with the Rave project using parameters	459	(1)
Ex 17.1 Step 6 Setting the DataField properties of the DataText components	460	(2)
Ex 17.1 Step 7 Set the parameter values in the application	462	(1)
Project Parameters	462	(1)
Ex 17.1 Step 8 Select a specific report	463	(1)
Global pages	463	(1)
Ex 17.1 Step 9 Add a common header to our reports	463	(1)
Mirroring	464	(1)
Report Variables	465	(1)
Example 17.2 Create a Data Aware report using Bands	465	(5)
Ex 17.2 Step 1 Add a RvDataSetConnection component	465	(1)
Ex 17.2 Step 2 Design a new report in Rave project LibraryReports.rav	466	(1)
The Data Viewer (Delphi 8)	466	(1)
Ex 17.2 Step 3 Add the global header from GlobalPage1	466	(1)
Ex 17.2 Step 4 Create the report title, the Region and the Bands	467	(1)
Bands and Regions	468	(1)
Ex 17.2 Step 5 Add the column headers and fields	468	(1)
Ex 17.2 Step 6 Generate the report from the application	469	(1)
Example 17.3 Create a data aware report using an SQL query	470	(2)
Ex 17.3 Step 1 Add the dbExpress, Data Access and Rave components	470	(1)
Ex 17.3 Step 2 Define the new report in Rave	471	(1)
Ex 17.3 Step 3 Create the event handler	472	(1)
Example 17.4 More detail through a more sophisticated SQL	472	(6)
Ex 17.4 Step 1 Develop and test the SQL query in MySQL Control Center	473	(2)
Ex 17.4 Step 2 Add dbExpress and Data Access components to provide the correct Data View for the report	475	(1)
Ex 17.4 Step 3 Define the new report in Rave	476	(2)
Ex 17.4 Step 4 The event handler	478	(1)
Example 17.5 Neaten up the application	478	(3)
Ex 17.5 Step 1 Create the procedure	479	(1)
Ex 17.5 Step 2 Change the event handlers	480	(1)
Review	481	(1)
Important Concepts	481	(1)
New Delphi Features	482	(3)
Problems	485	(1)
Investigating objects	486	(49)
Purpose of this Chapter
Example 18.1 The basic `unit' file	487	(2)
The unit name	487	(1)
The interface section	488	(1)
The implementation section	488	(1)
Example 18.2 Extending the basic application	489	(2)
Changing the form's name	490	(1)
Adding buttons	490	(1)
Adding event handlers	491	(1)
Example 18.3 Creating our own classes and objects	491	(6)
Ex 18.3 Step 1 The overall framework	492	(1)
Ex 18.3 Step 2 The TCounter class	493	(1)
The Code Explorer	494	(1)
Ex 18.3 Step 3 Using the class	495	(2)
Example 18.4 Extending TCounter	497	(11)
Ex 18.4 Step 1 Inheriting from TCounter	497	(2)
Ex 18.4 Step 2 Using the new class	499	(4)
Navigating through the Code Explorer	503	(1)
The Project Browser	503	(1)
Simple object orientation (OO)	504	(1)
Basic object-orientation principles	504	(1)
Classes and objects	505	(1)
Encapsulation	506	(1)
Efficiency, reliability and re-use through inheritance	506	(2)
Composition -- combining objects	508	(1)
Example 18.5 The Sender parameter in event handlers	508	(6)
Ex 18.5 Step 1 Static design (user interface)	509	(1)
Ex 18.5 Step 2 The OnClick event handler (version 1)	510	(1)
Ex 18.5 Step 3 Using the Sender parameter	510	(1)
Ex 18.5 Step 4 Linking in the other SpeedButtons	511	(1)
Ex 18.5 Step 5 Testing the Sender parameter	512	(1)
Ex 18.5 Step 6 Substitution	512	(1)
Ex 18.5 Step 7 An alternative typecasting operator	513	(1)
Ex 18.5 Step 8 The equality operator	514	(1)
Review	514	(1)
Important Concepts	515	(1)
New Delphi Features	516	(1)
Problems	517	(4)
Appendices
Appendix 1 Deployment	521	(5)
Appendix 2 File types	526	(2)
Appendix 3 Component naming conventions	528	(2)
Appendix 4 Installation notes	530	(5)
Index	535