Basics of Database Programming with VB6 By: Mr. Carl Michael L. Morados.
-
Upload
jada-mclain -
Category
Documents
-
view
223 -
download
8
Transcript of Basics of Database Programming with VB6 By: Mr. Carl Michael L. Morados.
Basics of Database Programming with VB6
By: Mr. Carl Michael L. Morados
Presentor: Mr. Carl Michael L. Morados
What is a database?
Database – a collection of related data or information, that is stored, modified and transmitted.
Student Database
Personal Info
Grades
Payments
Presentor: Mr. Carl Michael L. Morados
Structure of a Database
Tables – collection of related information Records –single piece of information Fields – smallest unit of information that is
useful to users.
Presentor: Mr. Carl Michael L. Morados
Structure of a Database
Student Information Sheet
Name:Address:Contact No.:
Table
Record
Fields
Presentor: Mr. Carl Michael L. Morados
Visual Basic and Database
Front End – the user interface, which the program uses to interact with the user.
Back End – the database, where all data coming from the user are saved, to be retrieved later.
Presentor: Mr. Carl Michael L. Morados
Visual Basic and Database
The user interacts withthe program by user interface or screens.
(Visual Basic)
ADO ObjectDatabase Driver
(Database Application)
Presentor: Mr. Carl Michael L. Morados
What are database drivers?
It allows different programming languages to communicate or get information from different data sources.
Presentor: Mr. Carl Michael L. Morados
Using the ADODC Object
ADODC (ActiveX Data Object) – an object used to connect a Visual Basic program to a database.
ADODC Object on the toolbox
ADODC Object when placed on the form
Presentor: Mr. Carl Michael L. Morados
Inserting the ADODC Object
1. Go to Project menu, then choose Components. (or right click on the toolbox)
2. When the components dialog appears, choose Microsoft ADO Data Control 6.0.
Presentor: Mr. Carl Michael L. Morados
Inserting the ADODC Object
Components Dialog Window
Presentor: Mr. Carl Michael L. Morados
Connecting the ADODC to a database
Straight Connection Setting of the Database Provider and directly
specifying the path of the database (location). Using ODBC (Open Database
Connectivity) Creating a Data Source Name (DSN) using the
ODBC Administrator of Windows
Presentor: Mr. Carl Michael L. Morados
Steps in Connecting ADODC
Right Click on the ADO Object Connect the ADO by using the Connection
String or ODBC Data Sources
Presentor: Mr. Carl Michael L. Morados
Steps in Connecting ADODC
Choose the correct databaseprovider.
Presentor: Mr. Carl Michael L. Morados
Steps in Connecting ADODC
Specify the correct path ofthe database
Test the connection if the ADODCwhere able to communicate withthe data source.
Presentor: Mr. Carl Michael L. Morados
Steps in Connecting ADODC
Specify how the ADODC willconnect to the table.
Presentor: Mr. Carl Michael L. Morados
Structure of an ADODC commands
<adodc name>.RECORDSET.<method><adodc name>.RECORDSET.<method>
The Name of the adodc object Refers to the tableobject
Methods that canbe done to a table
Presentor: Mr. Carl Michael L. Morados
Types of ADODC methods
Record Operations Addnew – used to add records to the table. Delete – used to delete records from the table. Update – used to save records to the table. CancelUpdate – cancels any record-related
operations.
Presentor: Mr. Carl Michael L. Morados
Types of ADODC commands
Record Navigation Find <parameters> - used to find or search
records, based on key fields. Movefirst – go to the first record. Movelast – go to the last record. Movenext – go to the next record. Moveprevious – go to the previous record. Move(record no.) – go to a specified record no.
Presentor: Mr. Carl Michael L. Morados
Types of ADODC commands
Record Counters RecordCount – returns the number of records on
the table EOF – End of File, returns True if the record
pointer reaches the end of the table. BOF – Beginning of File, returns True if the record
pointer reaches the beginning of the table
Presentor: Mr. Carl Michael L. Morados
Finding Records
FIND “[key field] like ‘comparing value’e.g.
adoSTUD.RECORDSET.FIND “[LName] like ‘Locsin’”
In finding records, always REFRESH the table first. to complete the code:
adoSTUD.REFRESH
adoSTUD.RECORDSET.FIND “[LName] like ‘Locsin’”
Presentor: Mr. Carl Michael L. Morados
Using the SQL Statements
SQL (Structured Query Language) – is composed of series of statements and clauses, which, when combined, perform different actions.
Select Queries – returns a specific set of records, based on criteria
Action Queries – performs actions such as deleting, adding or updating records.
Presentor: Mr. Carl Michael L. Morados
Basic Structure of Select
SELECT <fields> FROM <tablename> [<where> <condition> <order by>]
e.g.
Select * from StudInfo