在VB6中用 Select 语句检索记录                  作者：unknown 更新时间： 2005-05-02                                              　　本文向你介绍如何不用借助Access，直接在程序中创建一个数据库，然后从标准的ASCII文本文件中读取数据到数据库中。原文是微软知识库中的一篇文章，但当时是针对VB3写的，所以其中的代码有点过时。例如现在DAO中已没有Table对象，代之以Recordset对象。下面是修改后的代码，在VB6中调试通过。                         　　首先在工程中添加对Microsoft DAO 3.51 Library引用。                         　　在窗体中添加三个命令按钮和两个MSFlexGrid.                         　　按照下表设置和控件的属性：                         　　控件 属性 值                         　　Command1 Caption "建立文本文件并显示在网格中"                         　　Command2 Caption "传输入数据并新建一个数据库"                         　　Command3 Caption "显示新数据库中的数据"                         　　Grid1 Cols 5                         　　Grid1 Rows 35                         　　Grid2 Cols 5                         　　Grid2 Rows 35                         　　将下面的代码添加到窗体的声明部分                         　　Dim nums(30) As Long                         　　Dim names(30) As String * 20                         　　Dim addresses(30) As String * 25                         　　Dim ss_nums(30) As String * 12                         　　Const DB_LONG = 4                         　　Const DB_TEXT = 10                         　　Const DB_LANG_GENERAL =                         ";LANGID=0x0809;CP=1252;COUNTRY=0"                         　　将下面的代码添加到窗体的Load事件中                         　　Sub Form_Load ()                         　　Show                         　　grid1.ColWidth(1) = 1000 'For Emp ID                         　　grid1.ColWidth(2) = 2000 'For Emp Name                         　　grid1.ColWidth(3) = 3000 'For Emp Addr                         　　grid1.ColWidth(4) = 2000 'For Emp SSN                         　　grid1.Col = 1                         　　grid1.Row = 0                         　　grid1.Text = "Emp ID" 'Header for Emp ID from text                         file                         　　grid1.Col = 2                         　　grid1.Row = 0                         　　grid1.Text = "Emp Name" 'Header for Emp Name from text                         file                         　　grid1.Col = 3                         　　grid1.Row = 0                         　　grid1.Text = "Emp Addr" 'Header for Emp Addr from text                         file                         　　grid1.Col = 4                         　　grid1.Row = 0                         　　grid1.Text = "Emp SSN" 'Header for Emp SSN from text                         file                         　　grid2.ColWidth(1) = 1000 'For Emp ID                         　　grid2.ColWidth(2) = 2000 'For Emp Name                         　　grid2.ColWidth(3) = 3000 'For Emp Addr                         　　grid2.ColWidth(4) = 2000 'For Emp SSN                         　　grid2.Col = 1                         　　grid2.Row = 0                         　　grid2.Text = "Employee ID" 'Header for Emp ID from DB                         　　grid2.Col = 2                         　　grid2.Row = 0                         　　grid2.Text = "Employee Name" 'Header for Emp Name from                         DB                         　　grid2.Col = 3                         　　grid2.Row = 0                         　　grid2.Text = "Employee Addr" 'Header for Emp ID from                         DB                         　　grid2.Col = 4                         　　grid2.Row = 0                         　　grid2.Text = "Employee SSN" 'Header for Emp Name from                         DB                         　　End Sub                         　　在Command1_Click事件中加入下面的代码                         　　Sub Command1_Click ()                         　　For i% = 1 To 30                         　　nums(i%) = i%                         　　names(i%) = "John Doe # " + Str$(i%)                         　　addresses(i%) = Str$(i%) + " Mocking Bird Lane"                         　　If i% < 9 Then                         　　'* Enter the following four lines as one, single line:                         　　ss_nums(i%) = Trim$(Str$(i%) + Trim$(Str$(i%))+                         Trim$(Str$(i%)) + "-" + Trim$(Str$(i% + 1))+                         Trim$(Str$(i% + 1)) + "-" + Trim$(Str$(i%))                         　　+ Trim$(Str$(i%)) + Trim$(Str$(i%)) + Trim$(Str$(i%)))                         　　Else                         　　'* Enter the following two lines as one, single line:                         　　ss_nums(i%) = Trim$(Trim$(Str$(999)) + "-" +                         Trim$(Str$(88))+ "-" + Trim$(Str$(7777)))                         　　End If                         　　Next i%                         　　Open "Testdata.DAT" For Output As #1                         　　For j% = 1 To 30                         　　Print #1, nums(j%)                         　　Print #1, names(j%)                         　　Print #1, addresses(j%)                         　　Print #1, ss_nums(j%)                         　　Next j%                         　　Close #1                         　　For i% = 1 To 30 'Display results from text file                         　　grid1.Col = 1                         　　grid1.Row = i%                         　　grid1.Text = nums(i%) 'Load Emp IDs                         　　grid1.Col = 2                         　　grid1.Row = i%                         　　grid1.Text = names(i%) 'Load Emp Names                         　　grid1.Col = 3                         　　grid1.Row = i%                         　　grid1.Text = addresses(i%) 'Load Emp Addrs                         　　grid1.Col = 4                         　　grid1.Row = i%                         　　grid1.Text = ss_nums(i%) 'Load Emp SSNs                         　　Next i%                         　　End Sub                         　　在Command2_Click事件中加入下面的代码                         　　Sub Command2_Click ()                         　　Dim newdb As Database                         　　Dim newtb As Recordset                         　　Dim newtd As New tabledef                         　　Dim newidx As New Index                         　　Dim field1 As New field 'For Emp nums                         　　Dim field2 As New field 'For Emp names                         　　Dim field3 As New field 'For Emp addresses                         　　Dim field4 As New field 'For Emp ss_nums                         　　screen.MousePointer = 11 'Display the time to build                         　　                         　　Set newdb = CreateDatabase("NEWDB.MDB",                         DB_LANG_GENERAL)                         　　                         　　newtd.Name = "Emp_Table" '* New table name                         　　field1.Name = "Emp_ID" '* Holds Employee ID nums()                         　　field1.Type = DB_LONG                         　　newtd.Fields.Append field1                         　　field2.Name = "Emp_Name" '* Holds Emp names()                         　　field2.Type = DB_TEXT                         　　field2.Size = 20                         　　newtd.Fields.Append field2                         　　field3.Name = "Emp_Addr" '* Holds Employee addr()                         　　field3.Type = DB_TEXT                         　　field3.Size = 25                         　　newtd.Fields.Append field3                         　　field4.Name = "Emp_SSN" '* Holds emp ss_nums()                         　　field4.Type = DB_TEXT                         　　field4.Size = 12                         　　newtd.Fields.Append field4                         　　newidx.Name = "Emp_ID_IDX" '* You have to have an                         index                         　　newidx.Fields = "Emp_ID"                         　　newidx.Primary = True                         　　newtd.Indexes.Append newidx                         　　newdb.TableDefs.Append newtd                         　　Set newtb = newdb.OpenRecordset("Emp_Table")                         　　Open "Testdata.dat" For Input As #1                         　　BeginTrans                         　　Do While Not (EOF(1))                         　　newtb.AddNew                         　　Line Input #1, tmp1$ 'Retrieve empl_id                         　　Line Input #1, tmp2$ 'Retrieve empl_name                         　　Line Input #1, tmp3$ 'Retrieve empl_addr                         　　Line Input #1, tmp4$                         　　newtb("Emp_ID") = Trim$(tmp1$) 'Place in field1                         　　newtb("Emp_Name") = Trim$(tmp2$) 'Place in field2                         　　newtb("Emp_Addr") = Trim$(tmp3$) 'Place in field3                         　　newtb("Emp_SSN") = Trim$(tmp4$) 'Place in field4                         　　newtb.Update 'Save to table                         　　Loop                         　　CommitTrans                         　　Close #1 'Close text file                         　　newtb.Close 'Close DB's table                         　　newdb.Close 'Close DB                         　　screen.MousePointer = 0 'Set back to show done                         　　End Sub                         　　在Command3_Click事件中加入下面的代码                         　　Sub Command3_Click ()                         　　Dim db As Database                         　　Dim t As Recordset                         　　Dim counter%                         　　Set db = OpenDatabase("NEWDB.MDB")                         　　Set t = db.OpenRecordset("Emp_Table")                         　　counter% = 1 'Start counter at Row=1                         　　Do Until t.EOF                         　　grid2.Col = 1                         　　grid2.Row = counter%                         　　grid2.Text = t(0) 'Load Emp ID                         　　grid2.Col = 2                         　　grid2.Row = counter%                         　　grid2.Text = t(1) 'Load Emp Name                         　　grid2.Col = 3                         　　grid2.Row = counter%                         　　grid2.Text = t(2) 'Load Emp Addr                         　　grid2.Col = 4                         　　grid2.Row = counter%                         　　grid2.Text = t(3) 'Load Emp SSN                         　　counter% = counter% + 1                         　　t.MoveNext                         　　Loop                         　　t.Close                         　　db.Close                         　　End Sub

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