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  • vb sqlite 使用 litex

    Private Declare Function LoadLibrary Lib "kernel32" Alias "LoadLibraryA" (ByVal lpLibFileName As String) As Long
    Dim oDB As Object
    Public dbPath As String '存储 数据库路径
    Private Sub Class_Initialize()
        Dim lb As Long
        lb = LoadLibrary(App.Path & "sqlite3.dll")
        Set oDB = CreateObject("LiteX.LiteConnection")
    End Sub
     
    Private Sub openDB()
        oDB.Open (dbPath)
    End Sub
     
    Public Function Insert(ByVal tableName As String, ByRef arr() As String) As String '插入 数据库的操作,返回受影响的行数,tableName为表名,arr为插入的字段名和值的二维数组
        Dim str_Fields As String, str_Values As String, strSql As String
        strSql = "insert into " & tableName
        For I = 0 To UBound(arr)
            str_Fields = str_Fields & "'" & arr(I, 0) & "',"
            str_Values = str_Values & "'" & Trim(Replace(arr(I, 1), "'", "''")) & "',"
        Next I
        str_Fields = Mid(str_Fields, 1, Len(str_Fields) - 1)
        str_Values = Mid(str_Values, 1, Len(str_Values) - 1)
        strSql = strSql & "(" & str_Fields & ") values (" & str_Values & ")"
        openDB (dbPath)
        oDB.Execute (strSql)
        Insert = oDB.changes
        oDB.Close
    End Function
     
    Public Function Query(ByVal tableName As String, Optional ByVal Fields As String = "", Optional Condition As String = "", Optional ByVal Exp As String = "") As String() '查询数据。返回结果数组,tableName 表名,fields是你要查询哪些字段,condition是查询条件也就是where, 为其它条件。例如order by ,group by,limit,offset等
        Dim arr() As String, sqlStr As String, K As Integer
        Dim odbRS As Object
        Set odbRS = CreateObject("LiteX.LiteStatement")
        Fields = IIf(Fields = "", "*", Fields)
        odbRS.ActiveConnection = oDB
        sqlStr = "select " & Fields & " from " & tableName & IIf(Condition = "", "", " where " & Condition & " ") & IIf(Exp = "", "", " " & Exp & " ")
        Debug.Print sqlStr
        openDB (dbPath)
        d = odbRS.prepare(sqlStr)
        If odbRS.Rows.Count = 0 Then
            Query = arr
        Else
            ReDim arr(odbRS.Rows.Count - 1, odbRS.Columns.Count - 1)
            For Each Row In odbRS.Rows
                For I = 0 To odbRS.Columns.Count - 1
                    arr(K, I) = Row(I)
                Next I
                K = K + 1
            Next
        End If
        Query = arr
        odbRS.Close
        oDB.Close
    End Function
     
    Public Function Modify(ByVal tableName As String, ByRef arr() As String, Optional Condition As String = "") As Integer'实现数据修改功能。tableName表名,arr和insert方法一样的。Condition 为条件,返回受影响的行数
        Dim str_ As String, strSql As String
        strSql = "update " & tableName & " set "
        For I = 0 To UBound(arr)
            str_ = str_ & "`" & Trim(arr(I, 0)) & "`='" & Trim(Replace(arr(I, 1), "'", "''")) & "',"
        Next I
        strSql = strSql & Mid(str_, 1, Len(str_) - 1) & IIf(Condition = "", "", " where " & Condition & " ")
        Debug.Print strSql
        openDB (dbPath)
        oDB.Execute (strSql)
        Modify = oDB.changes
        oDB.Close
    End Function
     
    Public Function Delete(ByVal tableName As String, Optional ByVal Condition As String = "") As Integer'删除数据的功能。tableName为表名,condition为条件,返回受影响的行数。
        Dim str_ As String
        strSql = "delete from " & tableName & IIf(Condition = "", "", " where " & Condition)
        Debug.Print strSql
        openDB (dbPath)
        oDB.Execute (strSql)
        Delete = oDB.changes
        oDB.Close
    End Function

    查询

     Dim sqlite As New ClsSqlite
        sqlite.dbPath = 这里搞上你的数据库的路径
        arr = sqlite.Query("这里是表名", "", "`username`='小松'")
    '将返回查询结果数组

    添加

    Private Function makeArr() As String()'本函数为制作一个要插入数据的数组。
        Dim arr() As String
        ReDim arr(2, 1)
        arr(0, 0) = "name" '这个是字段名
        arr(0, 1) = txtName.Text  '这个是字段值,下同
        arr(1, 0) = "oldname"
        arr(1, 1) = txtOldname.Text
        arr(2, 0) = "sex"
        arr(2, 1) = cmbSex.Text
        makeArr = arr
    End Function
    Private Sub cmdAdd_Click()
    Dim pSqlite As New ClsSqlite
    arr = makeArr  '这里调用makeArr得到要插入的数据的数组
    pSqlite.Insert("populations", arr) '执行插入
    End Sub

    3、修改
    修改和添加记录基本上差不多。也需要makeArr,唯一不同的是一个调用类里面的insert方法,一个调用类里面的modify方法,还有就是既然你要修改数据,需要指定条件,要修改哪个ID的数据。
    pSqlite.Modify("populations", arr, "`uid`='" & Uid & "'") 'uid就是指定要修改uid为UID的这一条数据。

    4、删除
    删除最简单。提供一个表名,和一个条件即可。

     
    利用本人提供的这个sqlite3的dll文件,你用vb6就不用复杂的操作,直接用LoadLibrary函数就可以直接操作sqlite数据库了。

    sqlite3 litex 版请下载此附件:

    附操作数据库的类模块代码以及使用方法。

    类模块代码【添加一个类,比如我们取名为ClsSqlite】
    将以下代码粘贴到类中:
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  • 原文地址:https://www.cnblogs.com/zanglaowei/p/4365286.html
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