VbzCart/procs/doCtgUpdate

About

• Purpose: building of ctg_upd* table contents
• Requires:
  • Reads:

1. REDIRECT Template:l/vc/query, qryCtg_Items_forUpdJoin, v_stk_items_remaining, qryCtg_Upd_join, qryCat_Titles

• • Writes: cat_items, data_tables
  • Scratch: ctg_upd1, ctg_upd2
• History:
  • 2008-03-15 Building sequence completely rewritten again, almost certainly including this procedure.
  • 2008-12-05 Added update of inactive catalog numbers (title's catalog number must match start of item's catalog number)
  • 2009-05-04 Added "UPDATE cat_items AS i LEFT JOIN qryCtg_Upd_join AS u ON i.ID=u.ID SET i.isInPrint=NULL, i.isForSale=NULL WHERE u.ID IS NULL;" as step 2 in stage 3. This prevents items having isInPrint still set even though isForSale is not set.

Status

This is mostly working. A key issue seems to be the correct setting of isForSale.

When we get to Stage 2:

• ctg_upd1 has all the generated data from active sources; these items are all for sale
• ctg_upd2 has joinable data from cat_items, i.e. anything which might be used (or revived) as a saleable item, i.e. anything where ID_Title is set. This includes a large number of items which will not be used. However, only items present in ctg_upd1 will cause a direct overwrite of cat_items, so we only need to save fields from cat_items which don't get set directly from ctg_upd1 (i.e. sourced items); items that are discontinued but in stock will not be overwritten, they will just have their stock status updated. This happens by setting those fields properly in ctg_upd2 (clear + calculate), then directly overwriting those fields in cat_items from the values in ctg_upd2. (Thus removing the need to clear those fields in cat_items even temporarily. This is the only reason we need ctg_upd2.)

The duplicate key count on ctg_upd2 should indicate how many different items share the same calculated IDS_Item. Ultimately, none of these should be items that are also for sale; perhaps a query should reality-check this after the update (for-sale items using duplicate IDSs), and warn the user if any records are found -- which would indicate a bug in the generation process.

During Stage 2, we first calculate (from scratch) quantities in stock and set the "for sale" flag for any items in stock (these go in ctg_upd2). Then we also set the "for sale" flag for any items which happen to have active sources, i.e. are in ctg_upd1.

Notes

• If this doesn't work as part of a script, check the actual syntax by editing the procedure in MySQL Query Browser.
• REPLACE INTO is MySQL-specific syntax. The same thing could be accomplished in other more standard ways, but in the interest of time this seemed like the best way to get things working.

To Do

• at some point, we need a way to test for duplicate IDS_Item keys before the data gets put into ctg_upd1. Duplicate keys will probably cause this procedure to fail at that point, but I don't know if it will show an informative message if this happens or just fail silently (as it is, even when it completes successfully it says "query cancelled").
  • Update 2009-05-03: It looks like ctg_upd2.cntDups is incremented whenever there's a duplicate, so all we have to do is check for rows with cntDups>1
• There should also be a check for catnums-needing-update but lacking CatSfx

SQL

<mysql>DROP PROCEDURE IF EXISTS `doCtgUpdate`; CREATE PROCEDURE doCtgUpdate() MODIFIES SQL DATA BEGIN

/* STAGE 1: Clear/refill the two temporary tables from which cat_items is updated. */

 /* == Clear temp tables == */
 DELETE FROM ctg_upd1;
 DELETE FROM ctg_upd2;

 /* == Fill temp tables == */
   /* -- generated source data: */
 INSERT INTO ctg_upd1 SELECT
   CatSfx, isCloseOut, ID_CTG_Title, ID_CTG_Item, ID_Title, ID_ItTyp, ID_ItOpt, ID_ShipCost, PriceBuy, PriceSell, PriceList,
   ItOpt_Descr_part, NameSng, GrpItmDescr, TitleGroupDescr, OptionDescr, ItOpt_Sort,
   GrpCode, GrpDescr, GrpSort, IDS_Item, CatNum, ItOpt_Descr 
 FROM qryCtg_src;

   /* -- existing catalog data indexed for JOINing: */
 INSERT INTO ctg_upd2 SELECT *, 0 AS cntDups
 FROM qryCtg_Items_forUpdJoin
 ON DUPLICATE KEY UPDATE cntDups=cntDups+1;

/* STAGE 2: Calculate stock numbers and set isForSale flag */

  /* -- calculate stock quantities; set for-sale flag if in stock */
 UPDATE ctg_upd2 AS i LEFT JOIN v_stk_items_remaining AS s ON i.ID_Item=s.ID_Item
 SET
   i.qtyInStock=s.QtyForSale,
   i.isForSale=(s.QtyForSale > 0);

  /* -- also set for-sale flag if available from source */
 UPDATE ctg_upd2 AS i LEFT JOIN ctg_upd1 AS u ON i.IDS_Item=u.IDS_Item
 SET i.isForSale=i.isForSale OR (u.IDS_Item IS NOT NULL);

/* STAGE 3: Update cat_items */

  /* -- replace sourced items in cat_items from CTG data (except for fields saved in ctg_upd2) */
 REPLACE INTO cat_items
 SELECT *
 FROM qryCtg_Upd_join;

 /* -- clear availability flags in any unused items */
 UPDATE cat_items AS i LEFT JOIN qryCtg_Upd_join AS u ON i.ID=u.ID SET i.isInPrint=NULL, i.isForSale=NULL WHERE u.ID IS NULL;

/* NOT FINISHED -- isn't there one more flag? */

  /* -- set stock and for-sale fields for *all* joinable cat_items from calculations done in ctg_upd2 */
 UPDATE cat_items AS i LEFT JOIN ctg_upd2 AS u ON i.ID=u.ID_Item
 SET
   i.isForSale=u.isForSale,
   i.qtyInStock=u.qtyInStock;

  /* -- update inactive catalog numbers where title's catnum has changed */
 UPDATE cat_items AS i LEFT JOIN qryCat_Titles AS t ON i.ID_Title=t.ID
 SET
   i.CatNum=CONCAT_WS("-",t.CatNum,i.CatSfx)
 WHERE (LEFT(i.CatNum,LENGTH(t.CatNum)) != t.CatNum) AND NOT isPulled;

/* STAGE 4: Housekeeping - update timestamp of cat_items so dependent tables will be recalculated */

 UPDATE data_tables SET WhenUpdated=NOW() WHERE Name="cat_items";

END; </mysql>