Question

我想为ID创建自定义值。例如，它将以“CR00001”开头，之后当我第二次保存数据时，它将增加数字部分（例如CR00002）。

以下是我正在使用的代码：

 Dim cr_id As String
 cr_id = "CR00001"
 Dim iReturn As Boolean

 Using SQLConnection As New MySqlConnection(strConnectionString)
     Using sqlCommand As New MySqlCommand()
         sqlCommand.Connection = SQLConnection
         With sqlCommand
             .CommandText = "INSERT INTO cr_record(idcr_record,Emplid,isu,Nama,date1,DeptDesc,email,change1,reasonchange,problem,priority,reasondescription,systemrequest,attachment) VALUES (@cr_id,@Emplid,@isu,@Nama,@date1,@DeptDesc,@email,@change1,@reasonchange,@problem,@priority,@reasondescription,@systemrequest,@attachment)"
             .CommandType = Data.CommandType.Text
             .CommandTimeout = 5000
             .Parameters.AddWithValue("@cr_id", cr_id)

Answer 1

如果要生成新ID，请编写一个用于生成ID的函数，并在此处复制此代码。将返回类型保留为String以返回newId。

    Dim newId As String
    Dim stringId As String
    Dim intId As Integer
    Dim conn As New System.Data.SqlClient.SqlConnection("Your database query string")
    Dim adpt As New System.Data.SqlClient.SqlDataAdapter("Select id from tableName Where date = (SELECT max(date) from tableName)", conn) 'Where tableName is you table
    Dim ds As New DataSet
    adpt.Fill(ds)
    If ds.Tables(0).Rows.Count = 0 Then 'This will check whether any records are there or not
        newId = "CR00001" ' If records are not there then this id will be returned
    Else
        stringId = ds.Tables(0).Rows(0).Item(0).ToString    'This will store your id in string format
        intId = stringId.Substring(2)       ' This will store only integer values from that id
        intId += 1      ' Increment id by 1
        newId = String.Concat("CR", intId)      ' Creating new Id incremented by 1
    End If
    Return newId

如何生成自定义ID

1 个答案: