Sample "queries" for datastore presentation

git-svn-id: svn://bknr.net/svn/trunk/projects/bos@2999 4281704c-cde7-0310-8518-8e2dc76b1ff0

queries-demo.lisp

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+;; With a traditional database, queries are typically formulated in a
+;; declarative query language like SQL.  With the BKNR datastore,
+;; no separate is needed as all data is stored in main memory, as
+;; regular Lisp objects.
+
+;; This file is meant to give you an impression how one can write
+;; queries in Lisp, using the BOS square meter selling application as
+;; an example database.
+
+(in-package :bos.m2)
+
+(enable-interpol-syntax)
+
+
+;; Number of sponsors
+
+;; SELECT COUNT(*) FROM SPONSOR
+
+(time (length (class-instances 'sponsor)))
+
+
+;; Find all sponsors that have "hans" in their name
+
+;; SELECT * FROM SPONSOR WHERE NAME LIKE "%hans%"
+
+(time (remove-if-not (lambda (sponsor)
+                       (ignore-errors (cl-ppcre:scan "(?i)hans" (user-full-name sponsor))))
+                     (class-instances 'sponsor)))
+
+
+;; Number of square meters
+
+;; SELECT COUNT(*) FROM M2
+
+(time (length (class-instances 'm2)))
+
+
+;; Number of square meters sold
+
+;; SELECT COUNT(*) FROM M2 WHERE CONTRACT IS NOT NULL
+
+(time (length (remove-if-not #'m2-contract (class-instances 'm2))))
+
+
+;; Number of contracts with sponsors from Germany
+
+;; SELECT COUNT(*) FROM CONTRACT C WHERE (SELECT COUNTRY FROM SPONSOR WHERE ID = C.ID) = 'NL'
+
+(time (length (remove "DE" (class-instances 'contract)
+                      :key (compose #'sponsor-country #'contract-sponsor)
+                      :test (complement #'equal))))
+
+
+;; Number of contracts with sponsors from Holland that are larger than 10 square meters.
+
+;; SELECT COUNT(*) FROM CONTRACT C, SPONSOR S WHERE S.COUNTRY = 'NL' AND (SELECT COUNT(*) FROM M2 M WHERE M.ID = C.ID) > 10
+
+(time (length (remove-if-not (lambda (contract) (and (equal "NL" (sponsor-country (contract-sponsor contract)))
+                                                     (> (length (contract-m2s contract)) 10)))
+                             (class-instances 'contract))))
+
+
+;; Find a particular sponsor
+
+;; SELECT * FROM SPONSOR WHERE EMAIL = "hans.huebner@gmail.com" LIMIT TO 1 ROW
+
+(defvar *sponsor* (time (find "hans.huebner@gmail.com" (class-instances 'sponsor) :key #'user-email :test #'equal)))
+
+
+;; Find the contracts with this sponsor
+
+;; SELECT * FROM CONTRACT WHERE SPONSOR_ID = [sponsor-id]
+
+(time (sponsor-contracts *sponsor*))
+
+
+;; Find out how many square meters that this sponsor "owns"
+
+;; SELECT COUNT(*) FROM M2 WHERE CONTRACT_ID IN (SELECT CONTRACT_ID FROM CONTRACT WHERE SPONSOR_ID = [sponsor-id])
+
+(time (apply #'+ (mapcar (compose #'length #'contract-m2s) (sponsor-contracts *sponsor*))))
+
+;; We can do it without consing
+
+(time (loop for contract in (sponsor-contracts *sponsor*)
+            sum (length (contract-m2s contract))))
+
+
+;; Determine the number of sponsors from each country
+
+;; SELECT COUNTRY, COUNT(*) FROM SPONSOR GROUP BY COUNTRY
+
+(time (mapcar (lambda (entry)
+                (list (car entry) (length (cdr entry))))
+              (group-on (class-instances 'sponsor)
+                        :key (compose #'make-keyword-from-string #'sponsor-country))))