VB.NET 不在 sql server 2008 express 中创建数据库

Posted 2023-03-23

【中文标题】VB.NET 不在 sql server 2008 express 中创建数据库

【英文标题】：VB.NET not creating database in sql server 2008 express

【发布时间】：2014-08-13 13:47:21

【问题描述】：

我正在开发一个 vb.net winform 项目，以将访客的详细信息纳入企业。我正在使用 sql server 2008 express 数据库来存储详细信息。 当应用程序启动时，它会检查数据库，如果存在则继续，如果不存在则在 sql server 2008 express 中创建数据库。 如果数据库不存在，则附加的代码应该创建数据库（好吧，无论如何都应该这样做）。该程序将通过应该创建数据库没有问题的代码，但会在 sqlCon.Open 的表单加载中引发错误，错误是：'无法打开登录请求的数据库“访问者”。登录失败。如果有人能告诉我哪里出错了，将不胜感激？

Private Sub allVisitors_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    Me.Text = "All Visitors"

    If Not checkDatabaseExists() Then

        Dim Result1 = MessageBox.Show("Database does not exist, press OK to continue and create database. Press Cancel to close.", "Create database", MessageBoxButtons.OKCancel)
        If Result1 = Windows.Forms.DialogResult.OK Then
            createVisitorsDatabase() 'Calls sub to create database
            createTablesForVisitors() 'Calls sub to create tables in database
        ElseIf Result1 = Windows.Forms.DialogResult.Cancel Then
            Me.Close()
            Exit Sub
        End If

        MessageBox.Show("Database has been created. Press OK to continue.", "Database created", MessageBoxButtons.OK)
    Else

        Dim Result2 = MessageBox.Show("Datebase exists, press OK to continue. Press Cancel to close.", "Dateabase exists", MessageBoxButtons.OKCancel)
        If Result2 = Windows.Forms.DialogResult.OK Then

        ElseIf Result2 = Windows.Forms.DialogResult.Cancel Then
            Me.Close()
            Exit Sub
        End If

    End If

    connectionString = "Data Source=.\SQLExpress;Initial Catalog=Visitors;Integrated Security=True;MultipleActiveResultSets=True"

    sql = "SELECT idNumber, firstName, lastName, company FROM visitorDetails"

    sqlCon = New SqlConnection(connectionString)

    sqlCon.Open() 'Error thrown here.
    'Error is : Cannot open database "Visitors" requested by the login. The login failed.

    sqlCmd = New SqlCommand(sql, sqlCon)

    da = New SqlDataAdapter(sql, sqlCon)

    dt = loadDtVisitorDetails()
    fillDgvVisitorDetails(dt)

    sqlCmd.Dispose()
    sqlCon.Close()

End Sub

Public Sub createVisitorsDatabase()

    connectionString = "Data Source=.\SQLExpress;Integrated Security=True;MultipleActiveResultSets=True"

    sql = "CREATE DATABASE Visitors"

    sqlCon = New SqlConnection(connectionString)

    sqlCon.Open()
    sqlCmd = New SqlCommand(sql, sqlCon)

    da = New SqlDataAdapter(sql, sqlCon)

    sqlCmd.Dispose()
    sqlCon.Close()

End Sub

Public Sub createTablesForVisitors()

    connectionString = "Data Source=.\SQLExpress;Integrated Security=True;MultipleActiveResultSets=True"

    sql = " USE Visitors " & _
   "CREATE TABLE visitorDetails " & _
   "(idNumber int NOT NULL, firstName varchar(25) NOT NULL, lastName varchar(40) NOT NULL, company varchar(150) NOT NULL, " & _
   "contactNumber varchar(50) NOT NULL, countryCode varchar(1000) NOT NULL, photoId varchar(1000) NULL, email varchar(150) NULL, PRIMARY KEY (idNumber)) " & _
   "CREATE TABLE reasonForVisit " & _
   "(idNumber int, dateOnSite varchar(20), reasonForVisit varchar(150))"

    sqlCon.Open()
    sqlCmd = New SqlCommand(sql, sqlCon)

    da = New SqlDataAdapter(sql, sqlCon)

    sqlCmd.Dispose()
    sqlCon.Close()
End Sub

【问题讨论】：

您好 - 检查您登录的默认数据库，并确保它没有设置（或空白）为您无权访问或不存在的数据库。如果不存在，则为空白，将其更改为 master 并重新测试。

【参考方案1】：

换行

da = New SqlDataAdapter(sql, sqlCon)

与

sqlCmd.ExecuteNonQuery()

执行您的 CREATE DATABASE。