Transcript Chapter 10 - itt

Chapter 10
Working With Databases
Starting Out with Visual Basic .NET 2nd Edition
10.1
Introduction
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Chapter 10 Topics
• Basic database terminology
• Fundamental database concepts
• ADO .NET for accessing databases
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10.2
What Is a Database?
The Data in a Database Is Organized in
Tables, Rows, and Columns
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Terminology
• Database: a collection of tables which hold
related data
• Table: data organized in rows and columns
• Field: an individual piece of information
pertaining to an item
• Record: a complete set of data about a
single item (a row in a table)
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Database Table
Row
(Record)
Column
Field
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10.3
ADO .NET
ADO .NET Is a Database Technology That
Allows You to Connect Your Visual Basic .NET
Applications to a Variety of Data Sources
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Application
Database
1. Create a connection to a Data Source
2. Create a Data Adapter (Object with
Methods) to facilitate the transfer of data
from the data source to the application
3. Create a dataset to hold the data in
memory while the application works
with it
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Application
Database
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10.4
ADO .NET Introduction
In This Chapter You Develop an Application
That Performs Basic Operations on a
Database, Such As Adding, Changing, and
Deleting Records, and Searching for Data
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Data Aware Controls
• Data Aware Controls can automatically
display data from a database
• These controls have a DataBindings
property
• For example, a TextBox control can be
bound to a column
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Creating a New Empty Row
• First declare an object to reference the row
Dim ObjectVar As System.Data.DataRow
• Then create the row by referencing a
specific DataSet
ObjectVar = DataSet.Table.NewRow
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Populating the Columns of the New Row
• Use the Item method to assign a value to a
column
ObjectVar.Item(ColumnName) = NewValue
• For example:
newDataRow.Item("fldInvNumber") = newInvNumber
newDataRow.Item("fldTitle") = newTitle
newDataRow.Item("fldArtist") = newArtist
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Adding the New Row to a Table
Saving the Updated Table to the Data Source
• To add the new row to the table
DataSet.Table.Rows.Add(ObjectVar)
• Saving the updated table to the data source
DataAdapter.Update(DataSet)
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Removing Records
• The CurrencyManager has a RemoveAt
method that removes a specified row from
the table
ObjectVar.RemoveAt(Index)
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Accessing Fields within a Table
DataSet.Table(Index).Field
•
•
•
•
DataSet is the name of the dataset
Table is the name of a table
Index is a row number
Field is the name of a field
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Putting Database Values Into
a List Box or Combo Box
Dim i As Integer
With DsCompactDiscs1
For i = 0 To (.tblCompactDiscs.Count - 1)
lstRecords.Items.Add _
(.tblCompactDiscs(i).fldTitle)
Next
End With
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Putting Radio Button Information
Into a Database
If radDog.Checked = True Then
DsDataSet1.tblData(rowNum).fldPet
ElseIf radCat.Checked = True Then
DsDataSet1.tblData(rowNum).fldPet
ElseIf radBird.Checked = True Then
DsDataSet1.tblData(rowNum).fldPet
ElseIf radOther.Checked = True Then
DsDataSet1.tblData(rowNum).fldPet
ElseIf radNone.Checked = True Then
DsDataSet1.tblData(rowNum).fldPet
End If
daAdapter.Update(DsDataSet1)
= "Dog"
= "Cat"
= "Bird"
= "Other"
= "None"
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