VBA two dimensional arrays connecting to a database

I am working with vba in excel and a database in access. The access database is a table that contains 3 columns; OrderIDs which is a column of numbers saying what order the particular item was in, OrderDescription which is a column that contains the description of the item, and Item # which is a column that gives a number to each particular item (if the item is the same as another, they both are the same item).

I need to build a 2-dimensional array in excel using VBA holding which items were purchased in which orders. The rows will be the Order ID and the columns will be the Item ID. The elements of this array will contain an indicator (like True or a “1”) that indicates that this order contains certain items. For example, row 6 (representing order ID 6) will have “True” in columns 1, 5, and 26 if that order purchased item IDs 1, 5, and 26. All other columns for that order will be blank.

In order to do this, i think I will have to determine the max order number (39) and the max item number(33). This information is available in the database which I can connect to using开发者_如何学编程 a .connection and .recordset. Some order numbers and some item numbers may not appear.

Note also that this will likely be a sparse array (not many entries) as most orders contain only a few items. We do not care how many of an item a customer purchased, only that the item was purchased on this order.

MY QUESTION is how can I set up this array? I tried a loop that would assign the values of the order numbers to an array and the items numbers to an array and then dimensioning the array to those sizes, but it wont work.

is there a way to make an element of an array return a value of True if it exists?

Thanks for your help

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It seems to me that the best bet may be a cross tab query run on an access connection. You can create your array with the ADO method GetRows : http://www.w3schools.com/ado/met_rs_getrows.asp.

TRANSFORM Nz([Item #],0)>0 AS Val
SELECT OrderNo
FROM Table
GROUP BY OrderNo
PIVOT [Item #]

With a Counter table containing integers from 1 to maximum number of items in a column (field) Num.

TRANSFORM First(q.Val) AS FirstOfVal
SELECT q.OrderNo
FROM (SELECT t.OrderNo, c.Num, Nz([Item #],0)>0 AS Val
FROM TableX t RIGHT JOIN [Counter] c ON t.[Item #] = c.Num
WHERE c.Num<12) q
GROUP BY q.OrderNo
PIVOT q.Num

Output:

OrderNo   1  2  3  4  5  6  7  8  9  10  11
                   0  0     0  0  0   0  
1        -1 -1          -1               -1
2        -1 -1 -1                        -1