vbnet数据库编程例子
VB.NET是一种基于.NET Framework的编程语言，它提供了强大的数据库编程功能。在本文中，我们将列举10个符合题目要求的VB.NET数据库编程例子，以帮助读者更好地理解和应用这些功能。
1. 连接数据库
连接数据库是数据库编程的第一步。在VB.NET中，我们可以使用SqlConnection类来实现与数据库的连接。下面是一个连接到SQL Server数据库的例子：
```vb
Imports System.Data.SqlClient
Dim connString As String = "Data Source=serverName;Initial Catalog=databaseName;User ID=userName;Password=password"sqltransaction什么意思
Dim conn As New SqlConnection(connString)
Try
    conn.Open()
    Console.WriteLine("数据库连接成功！")
Catch ex As Exception
    Console.WriteLine("数据库连接失败：" & ex.Message)
Finally
    conn.Close()
End Try
```
2. 执行SQL查询
在连接到数据库后，我们可以使用SqlCommand类来执行SQL查询。下面是一个查询数据库中所有员工信息的例子：
```vb
Dim query As String = "SELECT * FROM Employees"
Dim cmd As New SqlCommand(query, conn)
Try
    Dim reader As SqlDataReader = cmd.ExecuteReader()
    While reader.Read()
        Console.WriteLine("员工ID: " & reader("EmployeeID"))
        Console.WriteLine("姓名: " & reader("FirstName") & " " & reader("LastName"))
        Console.WriteLine("职位: " & reader("Title"))
        Console.WriteLine("----------")
    End While
Catch ex As Exception
    Console.WriteLine("查询失败：" & ex.Message)
End Try
```
3. 插入数据
插入数据是数据库编程中常见的操作之一。下面是一个向数据库中插入一条新员工信息的例子：
```vb
Dim query As String = "INSERT INTO Employees (FirstName, LastName, Title) VALUES (
@FirstName, @LastName, @Title)"
Dim cmd As New SqlCommand(query, conn)
cmd.Parameters.AddWithValue("@FirstName", "John")
cmd.Parameters.AddWithValue("@LastName", "Doe")
cmd.Parameters.AddWithValue("@Title", "Manager")
Try
    Dim rowsAffected As Integer = cmd.ExecuteNonQuery()
    Console.WriteLine("插入成功！影响行数: " & rowsAffected)
Catch ex As Exception
    Console.WriteLine("插入失败：" & ex.Message)
End Try
```
4. 更新数据
更新数据是修改数据库中已有记录的操作。下面是一个更新员工职位的例子：
```vb
Dim query As String = "UPDATE Employees SET Title = @Title WHERE EmployeeID = @EmployeeID"
Dim cmd As New SqlCommand(query, conn)
cmd.Parameters.AddWithValue("@Title", "Senior Manager")
cmd.Parameters.AddWithValue("@EmployeeID", 1)
Try
    Dim rowsAffected As Integer = cmd.ExecuteNonQuery()
    Console.WriteLine("更新成功！影响行数: " & rowsAffected)
Catch ex As Exception
    Console.WriteLine("更新失败：" & ex.Message)
End Try
```
5. 删除数据
删除数据是从数据库中删除记录的操作。下面是一个删除指定员工的例子：
```vb
Dim query As String = "DELETE FROM Employees WHERE EmployeeID = @EmployeeID"
Dim cmd As New SqlCommand(query, conn)
cmd.Parameters.AddWithValue("@EmployeeID", 1)
Try
    Dim rowsAffected As Integer = cmd.ExecuteNonQuery()
    Console.WriteLine("删除成功！影响行数: " & rowsAffected)
Catch ex As Exception
    Console.WriteLine("删除失败：" & ex.Message)
End Try

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