VBA 连接数据库步骤：

        1.创建连接对象

        2.打开连接

        3.执行SQL

        4.关闭连接

        5.释放连接对象

前提：在【工具】>【引用】ADO库

Sub conDatabase()
    
    Dim con As ADODB.Connection '声明对象变量
    Set con = New ADODB.Connection '创建对象变量
    'Dim con As New ADODB.Connection  ’这一行等效于以上两行
    
    '建立数据库连接
    'con.Open "provider=microsoft.ace.oledb.12.0;data source =" & ThisWorkbook.Path & "\test.accdb"  '连接access数据库
    'con.Open "provider=microsoft.ace.oledb.12.0;extended properties=excel 12.0;data source =" & _
    ThisWorkbook.Path & "\数据.xlsx"
    
    '以下写法等效于 con.Open
    With con
        .Provider = "microsoft.ace.oledb.12.0"
        .ConnectionString = ThisWorkbook.Path & "\test.accdb"
        .Open
    End With
    MsgBox "连接成功"
    Dim sql As String
    'sql = "insert into check(code,year,month,day) values ('1','2022','1','1')"
   sql = "insert into m_check(m_code,m_year,m_month,m_day) values (3,2022,1,1)"
   
    con.Execute (sql)
    
    con.Close   '关闭连接
    Set con = Nothing '释放变量
    
End Sub

注意事项：

1. 创建连接的两种写法

 Dim con As ADODB.Connection '声明对象变量
 Set con = New ADODB.Connection '创建对象变量

Dim con As New ADODB.Connection  ’这一行等效于以上两行

2.两种写法打开连接

con.Open "provider=microsoft.ace.oledb.12.0;data source =" & ThisWorkbook.Path & "\test.accdb"  '连接access数据库

With con
        .Provider = "microsoft.ace.oledb.12.0"
        .ConnectionString = ThisWorkbook.Path & "\test.accdb"
        .Open
End With

VBA使用SQL操作Excel，方法和上面连接Access操作相似只需将连接字符串更改成下面这种：

con.Open "provider=microsoft.ace.oledb.12.0;extended properties=excel 12.0;data source =" & _
    ThisWorkbook.Path & "\数据.xlsx"