Database Design Project: Swim Schools

Final Presentation

Susan Burtner Matthew Burke Sooyong Choi Sean Greene

Vishal Kapadia Rishabh Singhal

Brian Wong

Introduction

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•  Swim lessons for children and adults

•  Private, Semi-private, and Group Lessons

•  ~220 employees

•  > 9,000 customers

•  Locations in San Francisco, Half Moon Bay, San Bruno, Atherton

•  www.swimlpb.com

La Petite Baleen Swim Schools

EER Diagram + Schema

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EER Diagram

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Schema

1. Member_Family (FamilyID, SignUpDate) 2. Member (MID, FamilyID1, Lname, Fname, PhoneNumber, Email, Refers, EmergencyContactID3) 3. Emergency_Contact (EmergencyContactID, Lname, Fname, PhoneNumber) 4. Monthly_Tuition (MID2, Amount, DiscountID6) 5. Swimmer (SwimmerID, Sibling5, SSN27, MID2) 6. Discount (DiscountID, DiscountType, Amount, FamilyID1) 7. Account_Balance (MID2, AccountNumber, Balance, DiscountID6) 8. Miscellaneous_Fee (AppliesTo, Amount) 9. Report (IndexNumber, Date, Progress, SwimmerID5, RibbonID16) 10. Parent (ParentID) 11. Coach (CoachID, Trainer11, TrainsCoach) 12. Coach_to_Class (CoachID11, SeriesID13, ClassID14)

13. Class_Series (SeriesID, RibbonID16, Day31, Time31) 14. Class (ClassID, SeriesID13) 15. Administrative_Request (RequestID, MID2, FamilyID1,

SwimformationID17) 16. Ribbon_Level (RibbonID, IndexNumber9) 17. Swimformation (StaffID21, SwimformationID) 18. Skill (Skill_ID, Skill_Description) 19. Coach_Qualified_To_Teach (RibbonID16, CoachID11) 20. Class_Specifies_Goal (SeriesID13, RibbonID16) 21. Staff (StaffID, SSN27, EmployeeID26, Department) 22. Executive (ExecutiveID, SSN27, EmployeeID26, StaffID21, IsLeaderOf) 23. Techie (TechieID, StaffID21, SSN27, EmployeeID26, Qualifications) 24. Deck (DeckID, SSN27, EmployeeID26, StaffID21)

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Schema

25. DOD (DOD_ID, SSN27, EmployeeID26, StaffID21, Supervises) 26. Employee (EmployeeID, SSN27, DateOfHire, LocationID29) 27. Person (SSN, DateOfBirth, Fname, Lname, Address, Phone_number) 28. Technology (TechID, Type, DateOfPurchase) 29. Location (LocationID, State, City, Address, Zip, Size, NumberOfEmployees, NumberOfMembers, ClassID14) 30. Time_Slot_Instance (Day31, Time31) 31. Weekly_Time_Slot (Day, Time) 32. Group_Class (SeriesID13, NumOfInstructors, NumOfStudents, Location) 33. Semi_Private_Class (SeriesID13, NumOfInstructors, NumOfStudents, Location) 34. Private_Class (SeriesID13, Location) 35. Event (Date, Time, Location, LocationID29)

36. Customer_Appreciation_Day (Date35, Time35, Location35, NumOfAttendees, DOD_ID25) 37. Fundraiser (Date35, Time35, Location35, NumOfAttendees, MonetaryGoal) 38. Inventory (ItemID) 39. Inventory_Item (ItemID38, DatePurchased, ExpirationDate) 40. Item_for_Use (ItemID38, Usage) 41. Item_for_Sale (ItemID38, Price) 42. Pays_into(PaymentType, Amount, Date) 43. Executive_Manages_Employee(ExecutiveID22, EmployeeID26) 44. Executive_Organizes_Fundraiser(ExecutiveID22, EmployeeID26, Date35, Time35, Location35) 45. Techie_Manages_Technology(TechieID23, TechID28) 46. DOD_Manages_Deck(DeckID24, DOD_ID25)

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Schema

47. DOD_Manages_Swimformation(DOD_ID25, SwimformationID17) 48. Deck_Keeps_Track_Of(DeckID24, ItemID38) 49. Customer_Appreciation_Day_Has_Fee (FeeAppliesTo8, FeeAmount8, EventDate35, EventTime35, EventLocation35) 50. Deck_Supports_Coach(CoachID11, DeckID24) 51. Coach_Runs_Customer_Appreciation_Day (CoachID11, EventDate35, EventTime35, EventLocation35) 52. Swimmer_RegistersFor_Customer_ Appreciation_Day (SwimmerID5, EventDate35, EventTime35, EventLocation35) 53. Monthly_Tuition_AddsTo_Acct_Balance (MID2) 54. Location_Contains_Inventory(LocationID29, ItemID38)

55. Member_Family_Generates_Monthly_Tuition (FamilyID1, MID2) 56. MiscellaneousFee_AddsTo_AcctBalance (FeeAppliesTo8, FeeAmount8, MID2) 57. Member_Requests_Report (MID2, ReportIndexNumber9) 58. Coach_Keeps_TrackOf_ItemForUse(CoachID11, ItemID38) 59. Coach_Creates_Report (CoachID11, ReportIndexNumber9) 60. Class_OccursDuring_TimeSlotInstance(ClassID14, Day31, Time31) 61. Swimmer_SwimsInClass (SwimmerID5, ClassID14, SeriesID13) 62. Ribbon_Level_Has_Skills(RibbonID16, Skill_ID18)

Query 1: Optimizing Class Schedule

How do we ensure an optimal ratio of swimmers to coaches within each ribbon level? Ribbon level + Class

type + Number of swimmers & coaches +

Time slots

Integer program minimizes time slots

subject to ratio

Satisfied ratios while minimizing time slots

Q1: Class Schedule Process

Gij <= 30 for all i and all j

Sij <= 30 for all i and all j

Gij <= 6Yij for all i that are group lessons

Sij <= 2Yij for all i that are semi-private lessons

Pij = 1 for all i that are private lessons

Aij <= 10 for all i that are advanced or adult lessons

Yij >= 1 for each lesson

Gij + Sij + Pij + Aij - Zj = 0, for all time slots i corresponding to each ribbon level j

Gij = number of students in group lesson at time slot i that is of ribbon level j

Sij = number of students in semi-private

lesson at time slot i that is of ribbon level j Pij = number of students in private lesson at

time slot i that is of ribbon level j Aij = number of students in advanced or adult

lesson at time slot i that is of ribbon level j Yij = number of coaches qualified to teach

class i in time slot i that is of ribbon level j

Objective Function: Max Number of Students in Each Class

max z = Σ(Gij) + Σ(Sij) + Σ(Pij) + Σ(Aij) for all i and all j

Constraints Decision Variables

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Q1: Class Schedule SQL

/*  Part  1:  Determines  number  of  swimmers  in  each  ribbon  level.*/    SELECT  Swimmer_SwimsInClass.SeriesID13,  Count(Swimmer.SwimmerID)  AS  Num_Of_Swimmers  FROM  Swimmer  INNER  JOIN  Swimmer_SwimsInClass  ON  Swimmer.SwimmerID  =  Swimmer_SwimsInClass.SwimmerID5  GROUP  BY  Swimmer_SwimsInClass.SeriesID13;    /*  Part  2:  Determines  swimmers  according  to  ribbon  level  who  are  of  a  particular  class  type.  */    SELECT  Swimmer_SwimsInClass.ClassID14  AS  Time_Slot,  Class.SeriesID13  AS  Ribbon_Level,  Class.ClassType  AS  Class_Type  FROM  Class  INNER  JOIN  Swimmer_SwimsInClass  ON  Class.ClassID  =  Swimmer_SwimsInClass.ClassID14  GROUP  BY  Swimmer_SwimsInClass.ClassID14,  Class.SeriesID13,  Class.ClassType;    

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Q1: Class Schedule SQL

/*  Part  3:  Determines  the  number  of  coaches  qualified  to  each  ribbon  level.  */    SELECT  Coach_Qualified_To_Teach.RibbonID16  AS  Ribbon_Level,  Count(Coach_Qualified_To_Teach.CoachID11)  AS  Num_Coaches_Qualified  FROM  Coach_Qualified_To_Teach  GROUP  BY  Coach_Qualified_To_Teach.RibbonID16;  

Use custom macro in Access to export to Excel. Excel organizes data and computes Integer Program.

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Q1: Class Schedule Output Query 1a:

Query 1c:

Query 1b:

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Q1: Scheduling Sample Output Excel: Integer Program assigning students to time slots

Query 2: Quantifying Coach Effectiveness

How can we quantify a coach’s effectiveness to objectively compare his performance with other coaches? Time to ribbon

advancement: Coaches + Swimmers

Normalize base value as coaches gain

experience

Assign performance metric utilizing

average statistics

Q2: Performance Metric Process

• Extract average completion times (Xi) for skill i of all swimmers and (Ci) for skill i of a coach’s swimmers.

• Calculate base value (BV) from the difference between all valid Xi and Ci and normalize:

 

Base Value

• Extract the coach’s total number of months on the job (T) and the number of classes he/she teaches (N).

• Calculate the performance as a metric (M):

M = BV * (0.1 + 0.1 * N) * (0.5 + 0.1 * N)

Metric

Q2: Performance Metric Process

• Extract average completion times (Xi) for skill i of all swimmers and (Ci) for skill i of a coach’s swimmers.

• Calculate base value (BV) from the difference between all valid Xi and Ci and normalize:

Base Value

• Extract the coach’s total number of months on the job (T) and the number of classes he/she teaches (N).

• Calculate the overall performance (M):

Metric

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Q2: Performance Metric SQL

/* Extracts average skill completion times. */ SELECT Report.SkillID, Avg(DateDiff("d", [Report]![SkillStartDate], [Report]![SkillEndDate])) AS [Average Time] FROM Report GROUP BY Report.SkillID; /* Extracts average completion times of coach’s students. */ SELECT Coach_Creates_Report.CoachID11, Report.SkillID, Avg(DateDiff("d",[Report]![SkillStartDate],[Report]![SkillEndDate])) AS Average FROM Report INNER JOIN Coach_Creates_Report ON Report.[IndexNumber] = Coach_Creates_Report.[ReportIndexNumber9] GROUP BY Coach_Creates_Report.CoachID11, Report.SkillID; /* Extracts coach’s length of employment and number of classes taught. */

SELECT Coach.CoachID, Count(Coach_to_Class.ClassID14) AS Num_Classes, Avg(DateDiff("m",Employee.DateOfHire,Date())) AS Months FROM Employee, Coach INNER JOIN Coach_to_Class ON Coach.[CoachID] = Coach_to_Class.[CoachID11] WHERE Coach.[EmployeeID26] = Employee.[EmployeeID] GROUP BY Coach.CoachID;

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Q2: Performance Metric Output

Query 2a: Query 2b:

Query 2c:

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Q2: Performance Metric Example

Average Times for Skill Completion

Skill ID Average Time (in days)

1 35

2 41

3 32

4 39

5 45

6 42

7 37

8 46

9 38

10 43

Total: 398

Coach's Average Skill Completion

Skill ID Average Time (in days)

1 32

2 43

3 30

   

5 40

   

7 35

8 46

9 34

10 41

Total: 301

Score Components

Normalized Deviation

Months Teaching

Number of Classes

0.24371859 7 4

Final Performance Score:

0.17547739

Query 3: Managing Inventory

How do we determine the optimal frequency of inventory purchases?

Class days + Daily demand + Unit costs

+ Interest rates + Purchase date

Economic Order Quantity (EOQ) model

to minimize holding and ordering costs

Optimal frequency of inventory purchases

Q3: Inventory Management Process

Optimal Quantity (Q*) = Reorder Point (ROP) = Optimal Cycle Time (T*) x Lead Time Optimal Cycle Time (T*) =

Economic Order Quantity Formulas:

Q3: Inventory Management Process Assumptions

-  Daily Demand is known and constant

-  Delivery Lead Time is known and constant

as one day

-  Ordering cost, unit cost, and interest rate

are known and constant

-  250 School days (5 days per a week, 10 federal

holidays)

-  No quantity discounts

-  Purchase date updated whenever new order

placed

-  The annual interest rate is known as really small

Diagram

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Q3: Inventory Management SQL /*  Implements  the  EOQ  model  to  return  the  optimal  order  quantity  of  our  inventory  items.  */    SELECT  ItemID,  ItemName,  IIF(AmountofItem<=DailyDemand,  ‘Yes’,  ‘No’)  AS  Stockout,  round(sqr(2*[OrderingCost]*[DailyDemand  *250]/(InterestRate*ItemPrice)))  AS  OptimalQuantityQ,  IIF(LeadTime>0,  round(LeadTime*sqr(2*[OrderingCost]/  (DailyDemand  *250]*(InterestRate*ItemPrice))))  AS  ReorderPoint,  IIF([AmountofItem<=Daily  Demand,  Date(),([PurchaseDate]+round(((sqr(2*[orderingCost]*[Daily  Demand]/([InterestRate]*[ItemPrice])))/[DailyDemand])*250)))  AS  NextOrderDate;      FROM  Inventory        ORDER  BY  IIF([AmountofItem<=Daily  Demand,  Date(),([PurchaseDate]+round(((sqr(2*[orderingCost]*[Daily  Demand]/([InterestRate]*[ItemPrice])))/[DailyDemand])*250)));  

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Q3: Inventory Management Output

Query 4: Customer Retention

Is there a correlation between customer retention and customer registration method?

Sort customers by registration method

Use ribbon levels completed as a

metric for customer loyalty

Plot ribbon levels completed by method

to determine most effective marketing

strategy

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Q4: Customer Retention Process Plotting:

-  x-axis: number of ribbon levels a swimmer has completed, where 1 means he/she only participated in a single ribbon level and 10 meaning he/she progressed through all levels.

-  y-axis: number of registrations through various methods by customers.

upward slopes indicate that swimmers tend to stay for longer periods of time. downward slopes indicate more short-term swimmers.

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Q4: Customer Retention SQL

SELECT  Administrative_Request.MethodOfRegistration,  [CurrentRibbonLevel]-­‐[StartingRibbonLevel]+1  AS  NumberOfRibbons    FROM  (Member  INNER  JOIN  Swimmer  ON  Member.[MID]  =  Swimmer.[MID2])  INNER  JOIN  Administrative_Request  ON  Member.[MID]  =  Administrative_Request.[MID2]    ORDER  BY  Administrative_Request.MethodOfRegistration;  

NOTE: We added one to the difference between the starting ribbon and current ribbon levels because if students were still on their first ribbon level, using the number zero may have led the user to believe the student did not participate in any class.

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Q4: Customer Retention Output

Q4: Customer Retention Example

Ribbon Levels Completed vs. Customer Registrations by Method

Query 5: Preventive Maintenance

How can we avoid costly unplanned maintenance fixes?

Cost of (un)planned maintenance

+ Inventory type + Number of failures

Determine probability of failure

using Prof. Leachman’s model

Optimal time to conduct planned

maintenance

Q5: Maintenance Process

•  RODBC Package ‒ Download and install RODBC package to

read database files (.mdb) in R.

•  Microsoft Access ‒ Write the query, and save the table.

•  prevMaintenance.R Script ‒  Input frequency of maintenance checks.

‒  Time between maintenance, t, is in weeks.

•  R ‒  Run script, calling myPMFfunction.

‒ Minimum time interval between planned maintenance checks will be outputted.

Q5: Maintenance Model The idea behind scheduled preventative maintenance is that planned maintenance has a cost, c2, that is less than an unplanned maintenance cost, c1. We assume that a component like filters is “new” or “like new” after a maintenance, and we want to choose the best time, t between the last completed maintenance and the next required maintenance (called a cycle). We assume that t is modeled by a cumulative probability distribution function F(t). The expected cost per unit time is:

E(cost per unit time) = E(cost per cycle) / E(length of a cycle)  

E(cost per cycle) = c1 * Pr(Unplanned Maintenance) + c2 * Pr(Planned Maintenance) = c1 * F(t) + c2 * [1 – F(t)]

E(length of a cycle) =

 

The expected cost function G(t) is thus:   However, the function f(x) is not usually known, so we approximate it using what we already know about when tools fail. So let pk denote the fraction of failures that occurred k periods after maintenance, k = 1, 2, 3, … We can then express G(t) as

c1 * F(t) + c2 * [1 – F(t)] G(t) =

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Q5: Maintenance SQL

/*  Determines  the  item  type,  costs  of  planned  and  unplanned  maintenance,  and  computes  the  probability  of  failure  by  dividing  the  number  of  failures  by  the  difference  between  the  purchase  date  and  the  current  date.  Conditions  on  what  specific  item  is  being  looked  at.  */    SELECT  Inventory_Item.Type,  Inventory_Item.CostOfUnplannedMaintenance,  Inventory_Item.CostOfPlannedMaintenance,  (Inventory_Item.NumberOfFailures/  DateDiff(“d”,Inventory_Item.DatePurchased,Date()))  AS  ProbabilityOfFailure    FROM  Inventory_Item    WHERE  (((Inventory_Item.Type)=‘Motorized  Pump’));  

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Q5: Maintenance Analysis in R

##Before  you  can  use  the  R  package  RODBC,  make  sure  you  have  R  and  the  RODBC  package  installed  on  your  computer.  You  then  need  to  create  a  new  System  DSN  in  the  ODBC  Data  Source  Administrator,  found  under  Control  Panel  -­‐-­‐>  System  and  Security  -­‐-­‐>  Administrative  Tools  in  Windows  7.  You  will  use  this  DSN,  here  “MyDSN”,  to  connect  to  the  MS  Access  Database.    library(RODBC)  channel  <-­‐  odbcConnect("MyDSN")  data  <-­‐  sqlFetch(channel,  "Query5")  c1  <-­‐  data[1,2]  c2  <-­‐  data[1,3]  p  <-­‐  data[1,4]  myPMFfunction  <-­‐  function(c1,  c2,  t,  p)  {  L  <-­‐  length(t)  G  <-­‐  array(1,  dim=c(1,L))  pf  <-­‐  p*t  for  (i  in  1:L)  {  G[i]  <-­‐  (c1*pf[i]  +  c2*(1-­‐pf[i]))/(sum(pf[1:i])+t[i]*(1-­‐pf[i]))  

 }  print(min(G))  }  

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Q5: Maintenance Output

Query Result:

R Script Result:

Normalization Analysis

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Decomposing to 1NF and 3NF

Fundraiser (EventID, EventName, EventType, Location, StartTime, EndTime,

NumofAttendees, MonetaryGoal, NumRegistered, MoneyRaised)

3NF

1NF

Fundraiser (EventID, EventName, EventType, StreetAddress, City, Zip, StartTime, EndTime, NumOfAttendees, MonetaryGoal, NumRegistered, Money Raised)

Event_Info (EventID, EventName, EventType, StartTime, EndTime) Event_Location (EventID, StreetAddress, City) Event_Before (EventType, StreetAddress, City, NumRegistered, MonetaryGoal) Funds_After (EvenyType, StreetAddress, City, NumOfAttendees, MoneyRaised)

Decomposing to 3NF

Inventory_Item (ItemID, PurchaseDate, ExpectedExpirationDate, Type, CostOfPM, CostUPM, NumOfFailures)

3NF

Item_PM (ItemID, Type, CostOfPM, CostOfUPM, NumOfFailures) Item_Dates (ItemID, PurchaseDate, ExpectedExpirationDate)

Functional Dependency