Making Database Systems Usable University of Michigan H

Making Database Systems Usable University of Michigan H. V. Jagadish, Adriane Chapman, Aaron Elkiss, Magesh Jayapandian, Yunyao Li, Arnab Nandi, Cong Yu Mar 27, 2008 Christiano Santiago 1

Agenda n Users Expectations n The Persistence of Pain n The Painless Future n Conclusion n Q&A Mar 27, 2008 Christiano Santiago 2

Users Expectations Database interactions n Ability to query in a more sophisticated way, using complex query semantics n More precise and complete answers n Expectation of structure in the result set n Create and update databases Mar 27, 2008 Christiano Santiago 3

The Persistence Of Pain Mar 27, 2008 Christiano Santiago 4

Higher Level Presentation Data Model Painful Relations Mar 27, 2008 Christiano Santiago 5

Higher Level Presentation Data Model Painful Relations Simple concept versus Implementation X Flight info Mar 27, 2008 Christiano Santiago 6

Higher Level Presentation Data Model Painful Relations What are the fligth departure times from Detroit to Beijing? SELECT s. departure_time FROM schedule AS s, flight_info AS f, airports AS d, airports AS a WHERE s. id = f. schedule_id AND f. fid = d. id AND d. city_name = “Beijing” AND f. tid = a. id AND a. city_name = “Detroit” Mar 27, 2008 Christiano Santiago 7

Higher Level Presentation Data Model Painful Relations Problems n Large number of table n Poorly named entities n Poorly named fields n Joins are not intuitive n Recursive self-joins n SQL is too onerous n Dependency on DBA (please don’t leave!) Mar 27, 2008 Christiano Santiago 8

Multiple Ways to Access Data Painful Options Mar 27, 2008 Christiano Santiago 9

Multiple Ways to Access Data Painful Options Too much functionality and too many options X Mar 27, 2008 Christiano Santiago 10

Multiple Ways to Access Data Painful Options Barry Schwartz, The tyranny of choice. Scientific American, April 2004, pp. 71 -75 Mar 27, 2008 Christiano Santiago 11

Multiple Ways to Access Data Painful Options Perspectives n Design systems for customized value n Care about how well uses can get their job done n Forms-based interfaces have been the primary means to interact with databases n Provide simple querying tools for novice users and powerful tools for experts (customization) Mar 27, 2008 Christiano Santiago 12

Precision and Recall Unexpected Pain Mar 27, 2008 Christiano Santiago 13

Precision and Recall Unexpected Pain X Mar 27, 2008 Christiano Santiago 14

Precision and Recall Unexpected Pain Search engines error acceptance n Expectations are set correctly n Usually top few results do contain something relevant n If no relevant results were found, search it again n The web is so huge that no one knows exactly what is out there Mar 27, 2008 Christiano Santiago 15

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Precision and Recall Unexpected Pain Unable to query n Systems may impede users from querying the way they want n Scenario: world traveler with infinite flexibility and many destinations to visit X Mar 27, 2008 Christiano Santiago 17

Precision and Recall Unexpected Pain Unable to query n User’s versus form designer’s mental model of the data. n Users should be worried about how. They just need the what. n Challenge #1: it’s not easy to provide a straightforward and comprehensive way of specifying what a user wants when a query requires aggregation or multiple complex joins. n Challenge #2: performance, security access level, data or program errors may prevent users from running a query. Mar 27, 2008 Christiano Santiago 18

Precision and Recall Unexpected Pain Unexpected results n (Unexpected results) + (no explanation) = frustration Example 1 • The client record shows he has 2 cars but • There is only 1 car related to this client in the database. # of cars was a field in the Client table, with no referential Integrity with Car. Owner table Mar 27, 2008 Christiano Santiago 19

Precision and Recall Unexpected Pain Unexpected results n (Unexpected results) + (no explanation) = frustration Example 2 User is looking for cheap flights provided by her favorite airline: • Los Angeles for $75 • Boston for $100 $400 was less than half the • San Francisco for $400 (? ) average price for a ticket to San Francisco Mar 27, 2008 Christiano Santiago 20

Precision and Recall Unexpected Pain Unexpected results n Empty & non-empty results n Users may need to know where a result comes from n Users may need to know why a result is returned n System’s usability can be significantly affected when no explanation can be given Mar 27, 2008 Christiano Santiago 21

Errors In Query Construction Unseen Pain Mar 27, 2008 Christiano Santiago 22

Errors In Query Construction Unseen Pain Database Users versus Computer Scientists X Mar 27, 2008 Christiano Santiago 23

Errors In Query Construction Unseen Pain Mar 27, 2008 Christiano Santiago 24

Errors In Query Construction Unseen Pain Perspectives n Query purpose: provide information that the user doesn’t have n How do I provide a clear and precise “from” and “where” clause, if I don’t know the possibilities? n WYSIWYG Mar 27, 2008 Christiano Santiago 25

Errors In Query Construction Unseen Pain WYISWYG Assisted Querying using Instant-Response Interfaces Arnab Nandi & H. V. Jagadish - University of Michigan Mar 27, 2008 Christiano Santiago 26

Errors In Query Construction Unseen Pain WYISWYG n Google Earth approach n Can you image finding a location in a map using coordinates instead of zoom and rotation? Mar 27, 2008 Christiano Santiago 27

Database Creation Birthing pain Mar 27, 2008 Christiano Santiago 28

Database Creation Birthing pain Corporate Market versus Average User X Mar 27, 2008 Christiano Santiago 29

Database Creation Birthing pain Perspectives n Users want to store their data into databases but this is not an easy task Database schema n Table structure n Normalization n Relationships n Constraints n Mar 27, 2008 Christiano Santiago 30

Database Creation Birthing pain Perspectives n An everyday database n No clear view of required database structure n No comprehensive design at starting point n Structure grows as time passes n Structure grows incrementally n Need to support both structured and unstructured information Mar 27, 2008 Christiano Santiago 31

The Painless Future Mar 27, 2008 Christiano Santiago 32

The Painless Future Geographic Model n Joins between data sets using geographic or spatial location as the basis Mar 27, 2008 Christiano Santiago 33

The Painless Future Network Model n Graph or network representation of data. Mar 27, 2008 Christiano Santiago 34

The Painless Future Multidimensional Model n Data as points in multi-dimensional space Mar 27, 2008 Christiano Santiago 35

The Painless Future Tabular Model n People is used to seeing data represented in simple two-dimensional tables Mar 27, 2008 Christiano Santiago 36

The Painless Future Presentation Data Models Perspectives n Data manipulation through presentation data model versus view updates n Consistency among view options: geographic and textual views in synchrony n Data provenance: “why” and “where” related to result sets n Direct data manipulation n n Point-and-click, drag-and-drop, etc. New few number of algebra operators to support it n Schema-later (unstructured) and heterogeneous database design Mar 27, 2008 Christiano Santiago 37

Conclusion n Databases are extremely difficult for most people to interact with. n We must rethink the architecture of the database systems as a whole. n Presentation model as a distinct layer above usual logical data model. Mar 27, 2008 Christiano Santiago 38

Questions & Answers Mar 27, 2008 Christiano Santiago 39