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在VB6中用Select語句檢索記錄

  本文向你介紹如何不用借助Access,直接在程序中創建一個數據庫,然後從標准的ASCII文本文件中讀取數據到數據庫中。原文是微軟知識庫中的一篇文章,但當時是針對VB3寫的,所以其中的代碼有點過時。例如現在DAO中已沒有Table對象,代之以Recordset對象。下面是修改後的代碼,在VB6中調試通過。

  首先在工程中添加對MicrosoftDAO3.51Library引用。

  在窗體中添加三個命令按鈕和兩個MSFlexGrid.

  按照下表設置和控件的屬性:

  控件屬性值

  Command1Caption"建立文本文件並顯示在網格中"

  Command2Caption"傳輸入數據並新建一個數據庫"

  Command3Caption"顯示新數據庫中的數據"

  Grid1Cols5

  Grid1Rows35

  Grid2Cols5

  Grid2Rows35

  將下面的代碼添加到窗體的聲明部分

  Dimnums(30)AsLong

  Dimnames(30)AsString*20

  Dimaddresses(30)AsString*25

  Dimss_nums(30)AsString*12

  ConstDB_LONG=4

  ConstDB_TEXT=10

  ConstDB_LANG_GENERAL=";LANGID=0x0809;CP=1252;COUNTRY=0"

  將下面的代碼添加到窗體的Load事件中

  SubForm_Load()

  Show

  grid1.ColWidth(1)=1000'ForEmpID

  grid1.ColWidth(2)=2000'ForEmpName

  grid1.ColWidth(3)=3000'ForEmpAddr

  grid1.ColWidth(4)=2000'ForEmpSSN

  grid1.Col=1

  grid1.Row=0

  grid1.Text="EmpID"'HeaderforEmpIDfromtextfile

  grid1.Col=2

  grid1.Row=0

  grid1.Text="EmpName"'HeaderforEmpNamefromtextfile

  grid1.Col=3

  grid1.Row=0

  grid1.Text="EmpAddr"'HeaderforEmpAddrfromtextfile

  grid1.Col=4

  grid1.Row=0

  grid1.Text="EmpSSN"'HeaderforEmpSSNfromtextfile

  grid2.ColWidth(1)=1000'ForEmpID

  grid2.ColWidth(2)=2000'ForEmpName

  grid2.ColWidth(3)=3000'ForEmpAddr

  grid2.ColWidth(4)=2000'ForEmpSSN

  grid2.Col=1

  grid2.Row=0

  grid2.Text="EmployeeID"'HeaderforEmpIDfromDB

  grid2.Col=2

  grid2.Row=0

  grid2.Text="EmployeeName"'HeaderforEmpNamefromDB

  grid2.Col=3

  grid2.Row=0

  grid2.Text="EmployeeAddr"'HeaderforEmpIDfromDB

  grid2.Col=4

  grid2.Row=0

  grid2.Text="EmployeeSSN"'HeaderforEmpNamefromDB

  EndSub

  在Command1_Click事件中加入下面的代碼

  SubCommand1_Click()

  Fori=1To30

  nums(i)=i

  names(i)="JohnDoe#" Str$(i)

  addresses(i)=Str$(i) "MockingBirdLane"

  Ifi<9Then

  '*Enterthefollowingfourlinesasone,singleline:

  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

  '*Enterthefollowingtwolinesasone,singleline:

  ss_nums(i)=Trim$(Trim$(Str$(999)) "-" Trim$(Str$(88)) "-" Trim$(Str$(7777)))

  EndIf

  Nexti

  Open"Testdata.DAT"ForOutputAs#1

  Forj=1To30

  Print#1,nums(j)

  Print#1,names(j)

  Print#1,addresses(j)

  Print#1,ss_nums(j)

  Nextj

  Close#1

  Fori=1To30'Displayresultsfromtextfile

  grid1.Col=1

  grid1.Row=i

  grid1.Text=nums(i)'LoadEmpIDs

  grid1.Col=2

  grid1.Row=i

  grid1.Text=names(i)'LoadEmpNames

  grid1.Col=3

  grid1.Row=i

  grid1.Text=addresses(i)'LoadEmpAddrs

  grid1.Col=4

  grid1.Row=i

  grid1.Text=ss_nums(i)'LoadEmpSSNs

  Nexti

  EndSub

  在Command2_Click事件中加入下面的代碼

  SubCommand2_Click()

  DimnewdbAsDatabase

  DimnewtbAsRecordset

  DimnewtdAsNewtabledef

  DimnewidxAsNewIndex

  Dimfield1AsNewfield'ForEmpnums

  Dimfield2AsNewfield'ForEmpnames

  Dimfield3AsNewfield'ForEmpaddresses

  Dimfield4AsNewfield'ForEmpss_nums

  screen.MousePointer=11'Displaythetimetobuild

  Setnewdb=CreateDatabase("NEWDB.MDB",DB_LANG_GENERAL)

  newtd.Name="Emp_Table"'*Newtablename

  field1.Name="Emp_ID"'*HoldsEmployeeIDnums()

  field1.Type=DB_LONG

  newtd.Fields.Appendfield1

  field2.Name="Emp_Name"'*HoldsEmpnames()

  field2.Type=DB_TEXT

  field2.Size=20

  newtd.Fields.Appendfield2

  field3.Name="Emp_Addr"'*HoldsEmployeeaddr()

  field3.Type=DB_TEXT

  field3.Size=25

  newtd.Fields.Appendfield3

  field4.Name="Emp_SSN"'*Holdsempss_nums()

  field4.Type=DB_TEXT

  field4.Size=12

  newtd.Fields.Appendfield4

  newidx.Name="Emp_ID_IDX"'*Youhavetohaveanindex

  newidx.Fields="Emp_ID"

  newidx.Primary=True

  newtd.Indexes.Appendnewidx

  newdb.TableDefs.Appendnewtd

  Setnewtb=newdb.OpenRecordset("Emp_Table")

  Open"Testdata.dat"ForInputAs#1

  BeginTrans

  DoWhileNot(EOF(1))

  newtb.AddNew

  LineInput#1,tmp1$'Retrieveempl_id

  LineInput#1,tmp2$'Retrieveempl_name

  LineInput#1,tmp3$'Retrieveempl_addr

  LineInput#1,tmp4$

  newtb("Emp_ID")=Trim$(tmp1$)'Placeinfield1

  newtb("Emp_Name")=Trim$(tmp2$)'Placeinfield2

  newtb("Emp_Addr")=Trim$(tmp3$)'Placeinfield3

  newtb("Emp_SSN")=Trim$(tmp4$)'Placeinfield4

  newtb.Update'Savetotable

  Loop

  CommitTrans

  Close#1'Closetextfile

  newtb.Close'CloseDB'stable

  newdb.Close'CloseDB

  screen.MousePointer=0'Setbacktoshowdone

  EndSub

  在Command3_Click事件中加入下面的代碼

  SubCommand3_Click()

  DimdbAsDatabase

  DimtAsRecordset

  Dimcounter

  Setdb=OpenDatabase("NEWDB.MDB")

  Sett=db.OpenRecordset("Emp_Table")

  counter=1'StartcounteratRow=1

  DoUntilt.EOF

  grid2.Col=1

  grid2.Row=counter

  grid2.Text=t(0)'LoadEmpID

  grid2.Col=2

  grid2.Row=counter

  grid2.Text=t(1)'LoadEmpName

  grid2.Col=3

  grid2.Row=counter

  grid2.Text=t(2)'LoadEmpAddr

  grid2.Col=4

  grid2.Row=counter

  grid2.Text=t(3)'LoadEmpSSN

  counter=counter 1

  t.MoveNext

  Loop

  t.Close

  db.Close

  EndSub

       以上是三聯網為您介紹的在VB6中用Select語句檢索記錄,希望對您有所幫助。

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