text:
PRISM is a system that supports Schema Evolution by means of schema mapping and query rewriting. PRISM is a joint project of Politecnico di Milano and University of California, Los Angeles. The main investigators are:
Carlo A. Curino (contact author): [1]
Hyun J. Moon: [2]
Carlo Zaniolo: [3]
Supporting graceful schema evolution represents an unsolved problem for traditional information systems that is further exacerbated in web information systems, such as Wikipedia and public scientific databases: in these projects based on multiparty cooperation the frequency of database schema changes has increased while tolerance for downtimes has nearly disappeared. As of today, schema evolution remains an error-prone and time-consuming undertaking, because the DB Administrator (DBA) lacks the methods and tools needed to manage and automate this endeavor by (i) predicting and evaluating the effects of the proposed schema changes, (ii) rewriting queries and applications to operate on the new schema, and (iii) migrating the database.
Our PRISM system takes a big first step toward addressing this pressing need by providing: (i) a language of Schema Modification Operators (SMO) to express concisely complex schema changes, (ii) tools that allow the DBA to evaluate the effects of such changes, (iii) optimized translation of old queries to work on the new schema version, (iv) automatic data migration, and (v) full documentation of intervened changes as needed to support data provenance, database flash back, and historical queries. PRISM solves these problems by integrating recent theoretical advances on mapping composition and invertibility, into a design that also achieves usability and scalability. Wikipedia and its 240+ schema versions provided an invaluable testbed for validating PRISM tools and their ability to support legacy queries.
Furthermore, we address this issue by introducing a formal evolution model for the database schema structure and its integrity constraints, and use it to derive update mapping techniques akin to the rewriting techniques used for queries. Thus, we (i) propose a new set of Integrity Constraints Modification Operators (ICMOs), (ii) characterize the impact on integrity constraints of structural schema changes, (iii) devise representations that enable the rewriting of updates, and (iv) develop a unified approach for query and update rewriting under constraints. We then describe the efficient implementation of these techniques provided by our PRISM++ system. The effectiveness of PRISM++ and its enabling technology has been verified on a testbed containing the evolution histories of several scientific databases and web information systems, including the Genetic DB Ensembl (410+ schema versions in 9 years), and Wikipedia (240+ schema versions in 6 years).
On-line Demo
While the actual demo is available online at: Prism a tool for schema evolution support. The Demo is still under development and has limited functionalities w.r.t. the internal prototype, but we are working on it... stay tuned!
There is a Video of the Demo available at: http://yellowstone.cs.ucla.edu/schema-evolution/documents/videos/PRISM++.mov
Update rewriting functionalities are shocase in a Video of the Demo available at: http://yellowstone.cs.ucla.edu/schema-evolution/documents/Prism++.mov
There is a Video of the VLDB presentation at: http://yellowstone.cs.ucla.edu/schema-evolution/documents/prism-vldb2008.mov
"Update Rewriting and Integrity Constraint Maintenance in a Schema Evolution Support System: PRISM++" Carlo Curino Hyun J. Moon, Alin Deutsch, Carlo Zaniolo, PVLDB, (2011).
"Graceful database schema evolution: the prism workbench", Carlo A. Curino, Hyun J. Moon, Carlo Zaniolo, to appear in VLDB 2008 PDF
"Information Systems Integration and Evolution: Ontologies at Rescue", Carlo A. Curino, Letizia Tanca, Carlo Zaniolo, STSM 2008 PDF
"The PRISM Workwench: Database Schema Evolution Without Tears", Carlo A. Curino, Hyun J. Moon, MyungWon Ham, Carlo Zaniolo, DEMO paper at ICDE 2009.
@INPROCEEDINGS{curino-vldb2008a, author = {Carlo A. Curino and Hyun J. Moon and Carlo Zaniolo}, title = {Graceful database schema evolution: the prism workbench}, booktitle = {Very Large Data Base (VLDB)}, year = {2008} }
@INPROCEEDINGS{curino-stsm2008, author = {Carlo A. Curino and Letizia Tanca and Carlo Zaniolo}, title = {Information Systems Integration and Evolution: Ontologies at Rescue}, booktitle = {International Workshop on Semantic Technologies in System Maintenance (STSM)}, year = {2008} }
Commercial Competitors
Here we list a series of commercial tools which partially tackle the problem of Schema Evolution. None of this support automatic query rewriting and data migration impact analysis as done by prototype PRISM. Most of them focus on comparing schema versions and creating report of the differences. Another common features is analyzing the impact of the change w.r.t. other DB objects such as store procedures, views, constraints, but none of this provide analysis of the impact on query and applications.
- DB2 Change Management Expert [4]
- Oracle Change Management Pack [5]
- MySQL Workbench for Schema Change [6]
- SwisSQL DBChangeManager (MSSQL) (DB compare and synchronization) [7]
- Idera SQL Change [8]
- Embarcadero Change Manager [9]
- Red-Gate SQL Compare [10]
- Best Soft Tool [11]
- Toad® DBA Suite [12] [13]
- Aldon lifecycle management solution [14]
Useful Links
Detailed Description
The incessant pressure of schema evolution is impacting every database, from the world's largest (Source: http://www.businessintelligencelowdown.com/2007/02/top_10_largest_.html) ``World Data Centre for Climate featuring over 6 petabytes of data, to the smallest single-website DB. DBMSs have long addressed, and largely solved, the physical data independence problem, but their progress toward logical data independence and graceful schema evolution has been painfully slow. Both practitioners and researchers are well aware that schema modifications can: (i) dramatically impact both data and queries <bibref f="defbib.bib">iceis2008</bibref>, endangering the data integrity, (ii) require expensive application maintenance for queries, and (iii) cause unacceptable system downtimes. The problem is particularly serious in Web Information Systems, such as Wikipedia, where significant downtimes are not acceptable while a mounting pressure for schema evolution follows from the diverse and complex requirements of its open-source, collaborative software-development environment <bibref f="defbib.bib">iceis2008</bibref>. The following comment(From the SVN commit 5552 accessible at: http://svn.wikimedia.org/viewvc/mediawiki?view=rev&revision=5552). by a senior MediaWiki <bibref f="defbib.bib">mediawiki</bibref> DB designer, reveals the schema evolution dilemma faced today by DataBase Administrators (DBAs): This will require downtime on upgrade, so we're not going to do it until we have a better idea of the cost and can make all necessary changes at once to minimize it.
Clearly, what our DBA needs is the ability to (i) predict and evaluate the impact of schema changes upon queries and applications using those queries, and (ii) minimize the downtime by replacing, as much as possible, the current manual process with tools and methods to automate the process of database migration and query rewriting. The DBA would also like (iii) all these changes documented automatically for: data provenance, flash-backs to previous schemas, historical queries, and case studies to assist on future problems.
There has been much recent work and progress on theoretical issues relating to schema modifications including mapping composition, mapping invertibility, and query rewriting.
These techniques have often been used for heterogenous database integration; in the Panta Rhei Information Schema Manager (PRISM) we exploit them to automate the transition to a new schema on behalf of a DBA. In this setting, the semantic relationship between source and target schema, deriving from the schema evolution, is more crisp and better understood by the DBA than in typical database integration scenarios. Assisting the DBA during the design of schema evolution, PRISM can thus achieve objectives (i-iii) above by exploiting those theoretical advances, and prompting further DBA input in those rare situations in which ambiguity remains.
Therefore, PRISM provides an intuitive, operational interface, used by the DBA to evaluate the effect of a possible evolution steps w.r.t. redundancy, information preservation, and impact on queries. Moreover, PRISM automates error-prone and time-consuming tasks such as query translation, computation of inverses, and data migration. As a by-product of its use PRISM creates a complete, unambiguous documentation of the schema evolution history, which is invaluable to support data provenance, database flash backs, historical queries, and user education about standard practices, methods and tools.
PRISM exploits the concept of Schema Modification Operators (SMO) <bibref f="defbib.bib">BernsteinGMN08</bibref>, representing atomic schema changes, which we then modify and enhance by (i) introducing the use of functions for data type and semantic conversions, (ii) providing a mapping to Disjunctive Embedded Dependencies (DEDs), (iii) obtain invertibility results compatible to <bibref f="defbib.bib">fagin2007c</bibref>, and (iv) define the translation into efficient SQL primitives to perform the data migration. The system has been tested and validated against the benchmark for schema evolution defined in <bibref f="defbib.bib">iceis2008</bibref>, which is built over the actual database schema evolution history of Wikipedia (170+ schema versions in 4.5 years). Its ability to handle the very complex evolution of one of the ten most popular website of the World Wide Web (Source: http://www.alexa.com). offers an important validation of practical soundness and completeness of our approach.
While Web Information Systems represent an extreme case, where the need for evolution is exacerbated <bibref f="defbib.bib">iceis2008</bibref> by the fast evolving environment in which they operates, every DBMS would benefit from graceful schema evolution. In particular every DB accessed by applications inherently hard to modify like: public Scientific Databases accessed by applications developed within several independent institutions, DB supporting legacy applications (impossible to modify), and system involving closed-source applications foreseeing high adaptation costs. Transaction time databases with evolving schema represent an interesting scenario were similar techniques can be applied \cite{vldb2008b}.
The PRISM system, harness recent theoretical advances <bibref f="defbib.bib">deutsch03mars</bibref><bibref f="defbib.bib">fagin2007a</bibref> into practical solutions, through an intuitive interface, which masks the complexity of underling tasks, such as logic-based mappings between schema versions, mapping composition, and mapping invertibility. By providing a simple operational interface and speaking commercial DBMS jargon, PRISM provides a user-friendly, robust bridge to the practitioners' world. System scalability and usability have been addressed and tested against one of the most intense histories of schema evolution available to date: the schema evolution of Wikipedia, featuring in 4.5 years over 170+ documented schema versions and over 700 gygabytes of data <bibref f="defbib.bib">barzan</bibref>.
Related Works
Some of the most relevant approaches to the general problem of schema evolution are the impact-minimizing methodology of <bibref f="defbib.bib">Ra:2005vj</bibref>, the unified approach to application and database evolution of <bibref f="defbib.bib">1228375</bibref>, the application-code generation of <bibref f="defbib.bib">cleve2006</bibref> and the framework for metadata model management of <bibref f="defbib.bib">melnik03rondo</bibref> and the further contributions <bibref f="defbib.bib">bernstein03applying</bibref><bibref f="defbib.bib">bernstein03data</bibref><bibref f="defbib.bib">velegrakis03mapping</bibref><bibref f="defbib.bib">yu05semantic</bibref>. While these and other interesting attempts provide solid theoretical foundations and interesting methodological approaches, the lack of operational tools for graceful schema evolution observed by Roddick in <bibref f="defbib.bib">roddick95schema</bibref> remains largely unsolved twelve years later. PRISM represents, at the best of our knowledge, the most advanced attempt in this direction available to date.
The operational answer to the issue of schema evolution used by PRISM exploits some of the most recent results on mapping composition <bibref f="defbib.bib">nash05composition</bibref>, mapping invertibility <bibref f="defbib.bib">fagin2007c</bibref>, and query rewriting <bibref f="defbib.bib">deutsch03mars</bibref>. The SMO language used here captures the essence of existing works <bibref f="defbib.bib">BernsteinGMN08</bibref>, but extends them with functions, for expressing data type and semantic conversions. The translation between SMOs and Disjunctive Embedded Dependencies (DED) exploited here is similar to the incremental adaptation approach of <bibref f="defbib.bib">velegrakis03mapping</bibref>, but achieves different goals. The query rewriting portion of PRISM exploits theories and tools developed in the context of the MARS project <bibref f="defbib.bib">deutsch01ded</bibref><bibref f="defbib.bib">deutsch03mars</bibref>. The theories of mapping composition studied in <bibref f="defbib.bib">madhavan03composing</bibref><bibref f="defbib.bib">Fagin04composing</bibref><bibref f="defbib.bib">nash05composition</bibref><bibref f="defbib.bib">BernsteinGMN08</bibref>, and the concept of invertibility recently investigated by Fagin et al. in <bibref f="defbib.bib">fagin2007c</bibref><bibref f="defbib.bib">fagin2007a</bibref> support the notion of SMO composition and inversion.
The big players in the world of commercial DBMSs have been mainly focusing on reducing the downtime when the schema is updated <bibref f="defbib.bib">oraclewhitepaper</bibref> and on assistive design tools <bibref f="defbib.bib">db2changemanagementexpert</bibref>, and lack the automatic query rewriting features provided in PRISM. Other tools of interest are <bibref f="defbib.bib">chimera</bibref> and LiquiBase (Available on-line: http://www.liquibase.org/).
Further related works include the results on mapping information preservation by Barbosa et al. <bibref f="defbib.bib">BarbosaFM05</bibref>, the ontology-based repository of <bibref f="defbib.bib">bounif2006</bibref>, the schema versioning approaches of <bibref f="defbib.bib">jagadish97</bibref>. XML schema evolution has been addressed in <bibref f="defbib.bib">MoroML07</bibref> by means of a guideline-driven approach. Object-oriented schema evolution has been investigated in <bibref f="defbib.bib">Galante:2005eq</bibref>. In the context of data warehouse X-TIME represents an interesting step toward schema versioning by means of the notion of augmenting schema <bibref f="defbib.bib">GolfarelliLRV04</bibref><bibref f="defbib.bib">Rizzi07</bibref>. PRISM differs form all the above in terms of both goals and techniques.
<bibreferences />


text: Only Hangers designs and manufactures one of the largest and most sought after collection of clothes hangers in America. We use only the highest quality materials in all of our wooden, plastic and metal hangers. In addition, we offer all of our high quality hangers at below wholesale prices. Whether you are a retailer or just looking to organize and beautify your home, you'll discover that Only Hangers is the ONLY place to buy your clothing hangers!

subset: commoncrawl


text:
Pope Benedict: We Are 'Made for the Infinite'
The Holy Father wrote a letter emphasizing people's hard-wired instinct to know God for the current Communion Liberation conference.
Pope Benedict welcomed the 33rd Rimini Meeting, an annual gathering organized by the lay Catholic movement Communion & Liberation, by examining mankind's relation to the Infinite.
"To discuss the subject of man and his yearning for the Infinite means first and foremost recognizing his constitutive relationship with the Creator. Man is a creature of God," the Pope said in a letter for the start of the Aug. 19-25 gathering.
"Today," he said, "this word, "creature," seems to be out of fashion: It would be more likely to think of man as a self-fulfilled being and master of his own destiny."
But this worldview still means that man "attempts to grasp the Infinite." He does so by choosing "incorrect methods," such as "drugs, disordered sexuality, technologies that devour man, success at any price and with misleading forms of religiosity," Pope Benedict observed.
Communion & Liberation grew out of the teaching methods of its Italian founder Father Luigi Giussani. As a high-school teacher in 1950s Milan, he wanted to help young people live out their Catholic faith in everyday life. The group that emerged around him became known as Communion & Liberation.
Since 1980, the movement has held an annual "Meeting for the Friendship Among Peoples" in the Italian seaside resort of Rimini. The gathering is described as "an encounter among persons of different faiths and cultures" where "peace, socialization and a friendship among peoples may be established."
This year's event will bring more than 800,000 visitors from more than 20 nations to the Rimini Fiera conference center to enjoy seminars, guest speakers, exhibitions, cinema, theater, music and sporting events.
Pope Benedict told the conference that despite the "original sin" of our first parents, which ruptured the human race's relationship with God, every person still has "an aching desire to reconcile this relationship, resembling the signature sealed with fire in man's soul and his flesh by the Creator himself."
This instinct is summed up, he suggested, in Psalm 63, where the author pleads, "You, God, are my God; earnestly I seek you. I thirst for you; my whole being longs for you, in a dry and parched land where there is no water."
"Not only my soul, but every fiber of my flesh is made to encounter its peace and its fulfillment in God," said the Pope, reflecting upon the Old Testament text.
"This tension is impossible to eliminate from the heart of man: Even when one rejects or denies God, the thirst for the Infinite that inhabits man does not melt away," he said.
It is this hard-wired instinct, the Pope explained, that can lead some to mistakenly pursue "an arduous and sterile search for 'false infinites'" that only satisfy the soul for "an instant" because they attempt to "replace the real thirst for the true Infinite."
Pope Benedict told participants that truly recognizing we are "made for the Infinite" means pursuing "a journey of purification in order to leave the 'false infinities' behind." This requires a "conversion of the heart and the mind" to uproot all those promises things "that are false and seduce man, rendering him a slave."
Once a person undergoes this conversion, he wrote in his letter, then they are able to recognize they are "a creature, dependent on God," which is accompanied by the "joyful discovery" that they are "children of God" and have "the possibility of a completely free and fulfilled life."
How, though, can people bridge the gap between the finite and Infinite? The Pope said that this question leads us "straight to the core of Christianity": the incarnation of Jesus Christ.
"Ever since the Incarnation, from the moment when the Word became flesh, the overwhelming gap between finiteness and infiniteness vanished; the eternal and infinite God left his heaven and entered time."
It is then, said the Pope, that each person can discover "the truest dimension of human existence," as continually taught by the Father Giussani: "life as vocation."


text:
I really enjoyed writing The Upcycled Garden blog post I did last year so I thought I'd
do another one (or two) of them this year. Before you know it spring will be upon us
(hopefully sooner rather than later!) so why not get those gears turning and think about
what creative ways you can use and display unique items in your yard and garden
this summer? Take a look at this collection and let me know what you think!
Coffee cans + chain + paint = A unique hanging planter
Can garden via Against the wood grain
Upcycled garden hose door mat by Mark Kintzel
Mosaic wall with embedded teacups for succulents
Painted wash tub garden via Indulgy
Simple birdbath made from a grapevine wreath, terracotta saucer, and rope
Upcycled bottle hummingbird feeder by Dee Luxford via Etsy
Tub settee from CleverJunk via Junkmarketstyle
Chicken wire chandelier DIY from fun.kyti.me
Upcycled water fountain photo via Heartland Gardens
Bicycle lawn mower from Treehugger
Planter made from an old doll by Franglias Designs
Make a ginger-bird house to feed the birds like this one from Backyard Farming
Old sink on sewing machine base is now a unique planter. From Cherry Hill Cottage
Planter made from an old wagon & sewing machine base from Second Hand Rose
Use broken clay pot pieces in your planters to deter digging pests by gardengateenotes
Vertically hung garden fence edging serves as a unique trellis
Birdhouse chandelier
Recycled tin can hanging planters from Poppytalk
Old screen door used as a garden gate
Chicken coop car (It's a Yolkswagon)
Bowling ball + 714 marbles = unique garden art
Outdoor chandelier made with electric insulators by Brian at Gadget Sponge
Old electric glass insulators on copper pipes = unique garden art
Copper pipe windchimes by SarahMc
Flower art via Just Imagine
Have a great week!


text:
Scotty McCreery is on a roll.
The North Carolina native scored his second consecutive No. 1 single with "This Is It," which topped both the Billboard Country Airplay chart and Mediabase chart this week.
"This Is It," which Scotty co-penned with Frank Rogers and Aaron Eshuis about his then-fiancée Gabi Dugal, is featured on Scotty's 2018 album, Seasons Change. Scotty earned his first No. 1 in 2018 with the album's lead single, "Five More Minutes."
"I wrote 'This Is It' for Gabi," says Scotty. "It's our song. I played it for her just an hour after I proposed. I sang it to her at our wedding. She's who I see in my mind when I perform it on the road every night. Watching our love story become my second No. 1 hit is something Gabi and I will treasure always. I am so thankful to country radio and my fans who have stood with me from day one for making my dreams come true."
photo by Jim Casey


text:
So, I got a laptop for Christmas and almost immediately I started looking for laptop bags so that I could cart it around town (because I'm just so cosmopolitan that you'll often find me perched in trendy coffee shops sipping a latte while I stare intently into my computer screen…or not).
It was a great quest. It needed to be terribly functional, it needed to fit my particular laptop, it needed space for other stuff and it needed to be cute. (That was actually the first priority.)
I found several cute ones and agonized (sadly, yes that's a true statement) over which one to pick. I finally settled on this one:
I was so enamored with it on the Internet but now that it's in my possession….it reminds me of the diaper bag I had when JBelle was a baby. (And honestly, I didn't very much care for that bag.)
I'm trying to be enamored with it in person. I've shown it to people and been all, "isn't it great?" And really, it is. It's a well made bag. I fits all the requirements I had except possibly the cute one. It looked so cute in the picture but in my hands?
I feel I should be stuffing diapers, wipes & bottles in there.
On one hand, I feel as though I should keep the bag and get over my whiny self, on the other hand…why keep it if it's really not what I thought it was going to be?
I wrote the above part of this post about 5 days ago and upon completing it (but not publishing it), I had made my decision. The laptop bag had to go back. Unfortunately that meant shopping for another one. Since I really wanted to have one for the conference next week, I didn't want to chance trying to order one online again. That meant I had to go to an actual store. (shudders)
Y'all, I'm not a shopper. I'm severely decision challenged. Choices overwhelm me. Plus, I was on a budget. I wasn't going to spend more than I paid for the first bag.
Yadda yadda yadda, long story longer…cute laptop bags in the mall aren't cheap, even on sale. I look at largish handbags…still not seeing anything that fits my criteria. In Macys I find a Fossil purse that it just so cute! But…not big enough for the laptop. I eventually find myself in Dillards wandering through more expensive bags when I spot the same Fossil bags I'd seen at Macys. But these are marked 50% off and on the very top shelf is a bag that is big enough for my laptop! Now, it's not technically a laptop bag, so I know I'm going to have to find something to add protection and cushion but it's supah cute and $10 less than what I paid for the first bag. And then…when it rings up at the checkout counter? Another 30% off!! Fossil, FTW!
With the additional savings, I purchased a "laptop sleeve" at Target that will add support and cushioning (plus the color coordinates with the pattern!)
And there you have it. The Great Laptop Bag Hunt of '09 has come to an end. I faced my indecisiveness head-on and prevailed! I think I'm well on my way to year of thriving!
Disclaimer: I don't expect any sympathy over this faux-tragedy. Believe me, I know that in the grand scheme of things, this is so low on the list of ills and discomforts that it's not even laughable it's really rather pathetic.


text:
Listings in Process Automation and Consulting Services in Minneapolis
Lucy AI-Powered Knowledge Management by Equals 3
in Search, Process Automation, Document Management, Data Recognition and Extraction, Artificial Intelligence
Lucy transforms enterprise knowledge into an easy to access trove of crucial insights. Understanding both structured and unstructured data, she unifies and delivers data an organization owns, licenses and commissions through one simple interface.
6465 Wayzata Boulevard
Suite 220
Minneapolis, MN 55426
United States


text:
Our institution was recently in the New York Times for the focus we are placing on financial literacy. We require students to attend multiple sessions about how to manage their money and make sound financial decisions. I think this is a forward thinking initiative, and wish that I had something like this when I was an undergraduate. What really struck me about the article, though, is the language that is used to describe what we're teaching:
"Champlain… doesn't actually use the term financial literacy. The opposite of literacy, after all, smacks of ignorance. Nobody wants to be ordered into a classroom for being illiterate. So the college speaks of its "financial sophistication" offerings…"
This is something I am going to begin adopting in the way I approach information literacy and teaching. As terms, I think 'financial literacy' or 'information literacy' are fine. People know what you are talking about. But they carry a lot of baggage, especially when used around students.
I almost never use the term 'information literacy' in the classroom, because I don't want students thinking that I believe that they are information illiterate. If they think that, I've lost them. And in truth, I don't think they're information illiterate. I think they're bright as hell and often they teach me things. They are really comfortable and adept at searching the web. I just think they're not as sophisticated in their use and evaluation of information as they should be.
As part of our information literacy assessment, librarians got to look at annotated bibliographies handed in by first year students. In some of them there were rather questionable sources being used. Some included websites from high schools, some included only websites. People with a high level of information sophistication would include sources from a variety of formats. They would try to find sources that argued against their thesis, anticipating arguments. They would recognize bias and approach their problem with balance and objectivity.
I don't believe that students are information illiterate, they simply need a higher level of information sophistication. At first students are only drinking the Pabst Blue Ribbons of the information world. These are things like Wikipedia and biased blog websites, and sites in the top five hits of a Google search. This is fine is many instances, but I want to help them develop more refined information palettes. I also want them to enjoy the Moët et Chandons of research articles, reports, and information presented in a scholarly, balanced way.