2017高考冲刺班全日制:谁能给我解释一下这段代码的详细意思吗?

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Set con = New ADODB.Connection
Set rs = New ADODB.Recordset
con.CursorLocation = adUseClient
con.Open "Provider=Microsoft.Jet.OLEDB.3.51;Data Source=" & App.Path & "\dbnew.mdb;Persist Security Info=False"
sql = "SELECT Month(处警分析.出警日期) AS 出警日期, Sum(处警分析.死亡人数) AS 死亡人数总计, Count(*) AS 出警次数, Sum(处警分析.受伤人数) AS 受伤人数总计, Sum(处警分析.损失总计) AS 损失总计总计 From 处警分析 where Year(出警日期)='" + Cmbyear.Text + "' GROUP BY Month(处警分析.出警日期)"
rs.Open sql, con, adOpenKeyset, adLockPessimistic
If (rs.EOF) Then
MsgBox "对不起,没有符合数据!"
End If
'设置显示
Set DataGrid1.DataSource = rs
DataGrid1.Refresh

Set con = New ADODB.Connection
Set rs = New ADODB.Recordset
con.CursorLocation = adUseClient
con.Open "Provider=Microsoft.Jet.OLEDB.3.51;Data Source=" & App.Path & "\dbnew.mdb;Persist Security Info=False"

连接到制定的数据库dbnew.mdb

sql = "SELECT Month(处警分析.出警日期) AS 出警日期, Sum(处警分析.死亡人数) AS 死亡人数总计, Count(*) AS 出警次数, Sum(处警分析.受伤人数) AS 受伤人数总计, Sum(处警分析.损失总计) AS 损失总计总计 From 处警分析 where Year(出警日期)='" + Cmbyear.Text + "' GROUP BY Month(处警分析.出警日期)"

查询符合 这个条件的记录

rs.Open sql, con, adOpenKeyset, adLockPessimistic
If (rs.EOF) Then
MsgBox "对不起,没有符合数据!"
End If

打开数据库

如果没有符合的记录 提示 "对不起,没有符合数据!"

Set DataGrid1.DataSource = rs
DataGrid1.Refresh

设置显示的方式

打开数据库 查询指定字段数据 关闭数据库