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Database Design: Normalization University of California, Berkeley School of Information Management and Systems SIMS 202: Information Organization and Retrieval 8/28/97 Information Organization and Retrieval Review • Entity-Relationship Diagrams • Designing a database 8/28/97 Information Organization and Retrieval Entities • • • • • • • • Customer Invoice Employee Inventory Supplier Account Sales Rep Parts 8/28/97 • Timecard • Check Information Organization and Retrieval Functional areas • • • • • • • Ordering Inventory Supplies Shipping Personnel Payroll We will concentrate on Ordering and Inventory 8/28/97 Information Organization and Retrieval Ordering Normalization Rep# Sales-Rep Part# Cust# Customer Writes Orders Invoice Invoice# Rep# Cust# 8/28/97 Information Organization and Retrieval Invoice# Contains Quantity Line-Item Emp# Wage Employee ISA Hourly ER Model Company# Sales Sales-Rep Part# Part# Quantity Company# Cust# Customer Writes Orders Invoice Invoice# Rep# Invoice# Quantity Contains Line-Item Ordered Part Has Contains Cust# On-Order Supplied Part Part Part# Count Price 8/28/97 Supplier Information Organization and Retrieval Supplies Part# Cost Company# Mapping to a Relational Model • Each entity in the ER Diagram becomes a relation. • A properly normalized ER diagram will indicate where intersection relations for many-to-many mappings are needed. • Relationships are indicated by common columns (or domains) in tables that are related. • We will examine the tables for the Acme Widget Company derived from the ER diagram 8/28/97 Information Organization and Retrieval Employee SSN 123-76-3423 342-88-7865 486-87-6543 843-36-7659 … 8/28/97 Lastname Jones Smith Hendersen Martinez … Firstname Janet Thomas Charles Roberto … Middlename Birthdate Address City Mary 6/25/63 234 State Berkeley Frederick 8/4/70 12 Lambert Oakland Robert 9/23/61 44 Central Berkeley Garcia 7/8/58 76 Highland Berkeley … … … … Information Organization and Retrieval Sales-Rep SSN Rep # Sales 123-76-3423 1 $12,345.45 843-36-7659 2 $231,456.75 Hourly SSN Wage 342-88-7865 $12.75 486-87-6543 $20.50 8/28/97 Information Organization and Retrieval Customer Cust # COMPANY STREET1 Integrated Standards 1 Ltd. 35 Broadway STREET2 STATE ZIPCODE New York NY 02111 34 Bureaucracy Plaza Floors 1-172 3 Control Elevation Cyber Assicates Place Center Phildelphia PA 03756 Cyberoid NY 08645 35 Libra Plaza Nashua NH 09242 1 Broadway Middletown IN 32467 88 Oligopoly Place 3 Independence Parkway Sagrado TX 78798 Rivendell CA 93456 8 Little Mighty Micro 34 Last One Drive Orinda CA 94563 9 SportLine Ltd. 38 Champion Place Compton CA 95328 2 MegaInt Inc. 3 Cyber Associates General 4 Consolidated Consolidated 5 MultiCorp Internet Behometh 6 Ltd. Consolidated 7 Brands, Inc. 8/28/97 Floor 12 CITY Suite 882 Information Organization and Retrieval Invoice Invoice # Cust # 93774 84747 88367 88647 776879 65689 8/28/97 Rep # 3 4 5 9 2 6 Information Organization and Retrieval 1 1 2 1 2 2 Line-Item Invoice # Part # Quantity 93774 3 10 84747 23 1 88367 75 2 88647 4 3 776879 22 5 65689 76 12 93774 23 10 88367 34 2 8/28/97 Information Organization and Retrieval Part Part # 1 2 3 4 5 6 7 8 9 8/28/97 Name Price Count Big blue widget 3.76 2 Small blue Widget 7.35 4 Tiny red widget 5.25 7 large red widget 157.23 23 double widget rack 10.44 12 Small green Widget 30.45 58 Big yellow widget 7.96 1 Tiny orange widget 81.75 42 Big purple widget 55.99 9 Information Organization and Retrieval Joins Part # Invoice # Part # Quantity 93774 3 10 84747 23 1 88367 75 2 88647 4 3 776879 22 5 65689 76 12 93774 23 10 88367 34 2 1 2 3 4 5 6 7 8 9 Cust # COMPANY STREET1 Integrated Standards 1 Ltd. 35 Broadway 8/28/97 Rep # 3 4 5 9 2 6 1 1 2 1 2 2 STREET2 STATE ZIPCODE NY 02111 34 Bureaucracy Plaza Floors 1-172 3 Control Elevation Cyber Assicates Place Center Phildelphia PA 03756 Cyberoid NY 08645 35 Libra Plaza Nashua NH 09242 1 Broadway Middletown IN 32467 88 Oligopoly Place 3 Independence Parkway Sagrado TX 78798 Rivendell CA 93456 8 Little Mighty Micro 34 Last One Drive Orinda CA 94563 9 SportLine Ltd. 38 Champion Place Compton CA 95328 3 Cyber Associates General 4 Consolidated Consolidated 5 MultiCorp Internet Behometh 6 Ltd. Consolidated 7 Brands, Inc. Information Organization and Retrieval Floor 12 CITY New York 2 MegaInt Inc. Invoice # Cust # 93774 84747 88367 88647 776879 65689 Name Price Count Big blue widget 3.76 2 Small blue Widget 7.35 4 Tiny red widget 5.25 7 large red widget 157.23 23 double widget rack 10.44 12 Small green Widget 30.45 58 Big yellow widget 7.96 1 Tiny orange widget 81.75 42 Big purple widget 55.99 9 Suite 882 Today • Normalization • Effectiveness and Efficiency criteria for database designs • Advantages and failings of DBMS technology 8/28/97 Information Organization and Retrieval Normalization • Normalization theory is based on the observation that relations with certain properties are more effective in inserting, updating and deleting data than other sets of relations containing the same data • Normalization is a multi-step process beginning with an “unnormalized” relation – Hospital example from Atre, S. Data Base: Structured Techniques for Design, Performance, and Management. 8/28/97 Information Organization and Retrieval Normal Forms • • • • • • First Normal Form (1NF) Second Normal Form (2NF) Third Normal Form (3NF) Boyce-Codd Normal Form (BCNF) Fourth Normal Form (4NF) Fifth Normal Form (5NF) 8/28/97 Information Organization and Retrieval Normalization No transitive dependency between nonkey attributes All determinants are candidate keys - Single multivalued dependency 8/28/97 BoyceCodd and Higher Information Organization and Retrieval Functional dependencyof nonkey attributes on the primary key - Atomic values only Full Functional dependencyof nonkey attributes on the primary key Unnormalized Relations • First step in normalization is to convert the data into a two-dimensional table • In unnormalized relations data can repeat within a column 8/28/97 Information Organization and Retrieval Unnormalized Relation Patient # Surgeon # 145 1111 311 Surg. date Patient Name Jan 1, 1995; June 12, 1995 John White Patient Addr Surgeon 15 New St. New York, NY 243 1234 467 2345 189 Jan 8, 1996 Charles Brown 4876 145 Nov 5, 1995 Hal Kane 5123 145 May 10, 1995 Paul Kosher Charles Field 10 Main St. Patricia Rye, NY Gold Dogwood Lane Harrison, David NY Rosen 55 Boston Post Road, Chester, CN Beth Little Blind Brook Mamaronec k, NY Beth Little 6845 243 Apr 5, 1994 Dec 15, 1984 Ann Hood Hilton Road Larchmont, Charles NY Field 8/28/97 Postop drug Drug side effects Gallstone s removal; Beth Little Kidney Michael stones Penicillin, Diamond removal none- Apr 5, 1994 May 10, 1995 Mary Jones Surgery Information Organization and Retrieval rash none Eye Cataract removal Thrombos Tetracyclin Fever is removal e none none Open Heart Surgery Cholecyst ectomy Gallstone s Removal Eye Cornea Replacem ent Eye cataract removal Cephalosp orin none Demicillin none none none Tetracyclin e Fever First Normal Form • To move to First Normal Form a relation must contain only atomic values at each row and column. – No repeating groups – A column or set of columns is called a Candidate Key when its values can uniquely identify the row in the relation. 8/28/97 Information Organization and Retrieval First Normal Form Patient # Surgeon # Surgery DatePatient Name Patient Addr Surgeon Name 1111 145 01-Jan-95 John White 1111 311 12-Jun-95 John White 15 New St. New York, NY 15 New St. New York, NY 1234 243 05-Apr-94 Mary Jones 10 Main St. Rye, NY 1234 467 10-May-95 Mary Jones 2345 4876 5123 6845 6845 8/28/97 189 145 145 243 243 Charles 08-Jan-96 Brown 10 Main St. Rye, NY Dogwood Lane Harrison, NY 05-Nov-95 Hal Kane 55 Boston Post Road, Chester, CN 05-Apr-94 Ann Hood 15-Dec-84 Ann Hood Hilton Road Larchmont, NY Drug adminSide Effects Charles Field Gallstone s removal Kidney stones removal Eye Cataract removal Patricia Gold Thrombos is removal none none David Rosen Open Heart Surgery none Beth Little Cholecyst ectomy Demicillin Beth Little Michael Diamond Blind Brook Mamaronec 10-May-95 Paul Kosher k, NY Beth Little Hilton Road Larchmont, NY Surgery Penicillin rash none none Tetracyclin e Fever Cephalosp orin Charles Field Gallstone s Removal none Eye Cornea Replacem Tetracyclin ent e Charles Field Eye cataract removal Information Organization and Retrieval none none none Fever none 1NF Storage Anomalies • Insertion: A new patient has not yet undergone surgery -- hence no surgeon # -- Since surgeon # is part of the key we can’t insert. • Insertion: If a surgeon is newly hired and hasn’t operated yet -- there will be no way to include that person in the database. • Update: If a patient comes in for a new procedure, and has moved, we need to change multiple address entries. • Deletion (type 1): Deleting a patient record may also delete all info about a surgeon. • Deletion (type 2): When there are functional dependencies (like side effects and drug) changing one item eliminates other information. 8/28/97 Information Organization and Retrieval Second Normal Form • A relation is said to be in Second Normal Form when every nonkey attribute is fully functionally dependent on the primary key. – That is, every nonkey attribute needs the full primary key for unique identification 8/28/97 Information Organization and Retrieval Second Normal Form Patient # 1111 1234 2345 4876 5123 6845 8/28/97 Patient Name Patient Address 15 New St. New John White York, NY 10 Main St. Rye, Mary Jones NY Charles Dogwood Lane Brown Harrison, NY 55 Boston Post Hal Kane Road, Chester, Blind Brook Paul Kosher Mamaroneck, NY Hilton Road Ann Hood Larchmont, NY Information Organization and Retrieval Second Normal Form Surgeon # Surgeon Name 145 Beth Little 189 David Rosen 243 Charles Field 311 Michael Diamond 467 Patricia Gold 8/28/97 Information Organization and Retrieval Second Normal Form Patient # Surgeon # Surgery Date 1111 1111 1234 1234 2345 4876 8/28/97 Surgery Drug Admin Side Effects 145 Gallstones 01-Jan-95 removal Kidney Penicillin rash 311 stones 12-Jun-95 removal none none 243 Eye Cataract 05-Apr-94 removal Tetracycline Fever 467 Thrombosis 10-May-95 removal 189 Open Heart 08-Jan-96 Surgery Cephalospori n none 145 Cholecystect 05-Nov-95 omy Demicillin none none none none none 5123 145 6845 243 6845 243 Gallstones 10-May-95 Removal Eye cataract 15-Dec-84 removal Eye Cornea 05-Apr-94 Replacement Information Organization and Retrieval none none Tetracycline Fever 1NF Storage Anomalies Removed • Insertion: Can now enter new patients without surgery. • Insertion: Can now enter Surgeons who haven’t operated. • Deletion (type 1): If Charles Brown dies the corresponding tuples from Patient and Surgery tables can be deleted without losing information on David Rosen. • Update: If John White comes in for third time, and has moved, we only need to change the Patient table 8/28/97 Information Organization and Retrieval 2NF Storage Anomalies • Insertion: Cannot enter the fact that a particular drug has a particular side effect unless it is given to a patient. • Deletion: If John White receives some other drug because of the penicillin rash, and a new drug and side effect are entered, we lose the information that penicillin can cause a rash • Update: If drug side effects change (a new formula) we have to update multiple occurrences of side effects. 8/28/97 Information Organization and Retrieval Third Normal Form • A relation is said to be in Third Normal Form if there is no transitive functional dependency between nonkey attributes – When one nonkey attribute can be determined with one or more nonkey attributes there is said to be a transitive functional dependency. • The side effect column in the Surgery table is determined by the drug administered – Side effect is transitively functionally dependent on drug so Surgery is not 3NF 8/28/97 Information Organization and Retrieval Third Normal Form Patient # Surgeon # Surgery Date 8/28/97 Surgery Drug Admin 1111 145 1111 311 01-Jan-95 Gallstones removal Kidney stones 12-Jun-95 removal 1234 243 05-Apr-94 Eye Cataract removal Tetracycline 1234 467 10-May-95 Thrombosis removal 2345 189 08-Jan-96 Open Heart Surgery Cephalosporin 4876 145 05-Nov-95 Cholecystectomy Demicillin 5123 145 10-May-95 Gallstones Removal none 6845 243 none 6845 243 15-Dec-84 Eye cataract removal Eye Cornea 05-Apr-94 Replacement Information Organization and Retrieval Penicillin none none Tetracycline Third Normal Form Drug Admin 8/28/97 Side Effects Cephalosporin none Demicillin none none none Penicillin rash Tetracycline Fever Information Organization and Retrieval 2NF Storage Anomalies Removed • Insertion: We can now enter the fact that a particular drug has a particular side effect in the Drug relation. • Deletion: If John White recieves some other drug as a result of the rash from penicillin, but the information on penicillin and rash is maintained. • Update: The side effects for each drug appear only once. 8/28/97 Information Organization and Retrieval Boyce-Codd Normal Form • Most 3NF relations are also BCNF relations. • A 3NF relation is NOT in BCNF if: – Candidate keys in the relation are composite keys (they are not single attributes) – There is more than one candidate key in the relation, and – The keys are not disjoint, that is, some attributes in the keys are common 8/28/97 Information Organization and Retrieval Most 3NF Relations are also BCNF Patient # 1111 1234 2345 4876 5123 6845 8/28/97 Patient Name Patient Address 15 New St. New John White York, NY 10 Main St. Rye, Mary Jones NY Charles Dogwood Lane Brown Harrison, NY 55 Boston Post Hal Kane Road, Chester, Blind Brook Paul Kosher Mamaroneck, NY Hilton Road Ann Hood Larchmont, NY Information Organization and Retrieval Effectiveness and Efficiency Issues for DBMS • Focus on the relational model • Any column in a relational database can be searched for values. • To improve efficiency indexes using storage structures such as BTrees and Hashing are used • But many useful functions are not indexable and require complete scans of the the database 8/28/97 Information Organization and Retrieval Example: Text Fields • In conventional RDBMS, when a text field is indexed, only exact matching of the text field contents (or Greater-than and Lessthan). – Can search for individual words using pattern matching, but a full scan is required. • Text searching is still done best (and fastest) by specialized text search programs (Search Engines) that we will look at more later. 8/28/97 Information Organization and Retrieval Normalizing to death • Normalization splits database information across multiple tables. • To retrieve complete information from a normalized database, the JOIN operation must be used. • JOIN tends to be expensive in terms of processing time, and very large joins are very expensive. 8/28/97 Information Organization and Retrieval Advantages of RDBMS • Possible to design complex data storage and retrieval systems with ease (and without programming). • Support for ACID transactions – – – – 8/28/97 Atomic Consistent Independent Durable Information Organization and Retrieval Advantages of RDBMS • Support for very large databases • Automatic optimization of searching (when possible) • RDBMS have a simple view of the database that conforms to much of the data used in businesses. • Standard query language (SQL) 8/28/97 Information Organization and Retrieval Disadvantages of RDBMS • Until recently, no support for complex objects such as documents, video, images, spatial or time-series data. (ORDBMS are adding support these). • Often poor support for storage of complex objects. (Disassembling the car to park it in the garage) • Still no efficient and effective integrated support for things like text searching within fields. 8/28/97 Information Organization and Retrieval Assignment • Examine the Cookie database using Access and look at the ER Diagram for it posted on the assignments page. • Consider the possibilities of Book publications – What are the problems with the database? – What new fields would you add to the database, and where? – Draw a new ER diagram showing your design. 8/28/97 Information Organization and Retrieval pubid Cookie ER diagram accno BIBFILE CALLFILE Has call accno Libid Callno publishes Has index accno 8/28/97 PUBFILE INDXFILE libid pubid subid Information Organization and Retrieval Library Address, etc SUBFILE Has subject subid LIBFILE Has copy subject