problem understaing this vba code!

Hi all. I got a access vba 2000 code that i hardly understand what some of its part doing.
i need to learn this since i want to learn how to refrence these system tables.
I be happy if some expert explain to me what these part does.Thanks

part1:

Code:

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  Set rsMetadb = MetaDB.OpenRecordset("SysKeys")

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part2:

Code:

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For Each idx In tbl.Indexes
            bUpdate = False
            rsMetadb.AddNew
            rsMetadb("Tablename") = tbl.Name
        If idx.Primary = True Or idx.Unique = True Then rsMetadb("Keyname") = idx.Name

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part3:

Code:

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  If bUpdate Then rsMetadb.Update

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part4:

Code:

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  rsMetadb("Keytype") = "PRIMARY"

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complete code:

Code:

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Dim bUpdate, ref As String
  Dim i As Integer


  Set rsMetadb = MetaDB.OpenRecordset("SysKeys")

  For Each tbl In db.TableDefs
    If Left(tbl.Name, 4) <> "MSys" Then
    For Each idx In tbl.Indexes
            bUpdate = False
            rsMetadb.AddNew
            rsMetadb("Tablename") = tbl.Name
        If idx.Primary = True Or idx.Unique = True Then rsMetadb("Keyname") = idx.Name
      'Check primary key
        If idx.Primary = True Then
            rsMetadb("Keytype") = "PRIMARY"
            bUpdate = True
        Else
      'Check Alternate key
          If idx.Unique = True And idx.Primary = False And idx.Foreign = False Then
            rsMetadb("Keytype") = "ALTERNATIVE"
            bUpdate = True
          End If
        End If
      If bUpdate Then rsMetadb.Update
    Next idx
    End If
  Next tbl
rsMetadb.Close

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From what I understand in this code is that you are opening a recordset called "SysKeys" then scanning through all of the tables and appending either the primary key or each alternative key to the "SysKeys" table..

Some of this code suggests further declarations are somewhere in your code and you are also using DAO, there is also a boolean variable decalred as variant..

Part one open up the table "SysKeys" in a recordset
Part Two Loop around the keys in the table, this is the primary key
Part Three doesn't update the recordset until bUpdate is True
Part Four Setting the field "KeyType" to be primary.