Databases Database A database is a collection of
Databases
Database �A database is a collection of data arranged for ease and speed of search and retrieval (The American Heritage Dictionary of English Language, 2000). �The quality of being ". . . arranged for ease and speed of search and retrieval" is what distinguishes a database from a computer network.
Database �Although databases can be accessed through the Internet, their contents are not retrieved by search engine services (such as Google or Yahoo!). �Some databases are available on CD-ROM and networked in some institutions through a subscription
Database (review) �Every database contains certain types and amounts of information referred to as coverage.
Elements of database coverage � What kinds of documents? (journals, magazines, book chapters, dissertations, audio files, statistical tables, images, web pages, software applications? ) � Which disciplines? (sociology, chemistry, music, all, none? ) � What time [periods]? (the current year? 1950 -1990? how often is the database updated? hourly? daily? weekly? monthly? annually? ) � What languages? (English only? other languages? ) � Which publication types? (scholarly? popular? trade? all? other? ) � What is included in the record? (a whole chapter? article? brief description such as bibliographic citation? abstract? ) publisher and title? )
Organization of a database �Databases store information in tables; tables store records; each record has fields �Databases are generally organized by fields, records, and files.
�A field is a single piece of information about an object; �If the object were an Employee, a field could be First name, Last name, or Date of birth.
�A record is one complete set of fields; In an Employee file, there would be one record for John Smith, another record for Mary Brown, and another record for Sue Black � A file is a collection of related records.
Database examples Examples of databases you may encounter in your daily life are: a telephone book T. V. Guide airline reservation system motor vehicle registration records papers in a filing cabinet files on your computer hard drive.
Understanding searches �Databases store data or information in tables, just like the one below:
Understanding searches �The table allows one to see all the records stored in the database �Tables can store many records
�A record is all of the data or information about a thing (or a person). Each bit of information is a field.
How many fields are related to this record?
Activity �Create a record with fields for a driver’s licence List as many fields as you think is necessary for a drivers licence
Field Searching �Most searches (e. g. using a search engine, databases) search for “words anywhere” or “keywords” automatically �This type of search retrieves more information with less precision �This is known as “recall” searching (it focuses on recalling as much information as possible)
�Most retrieval systems allow searching in specific fields (e. g. author, title) and usually refer to this as “advanced” or “expert” searching �This kind of searching typically retrieves. . .
�. . . less information with more precision (referred to as precision searching)
Think about it �If you are a detective and the only clues you have for a missing persons case are the words "red, " "blue, " and "green, “. Who is the missing person? What kind of search would this be?
Think about it �This is keyword searching �When you do a keyword search or an "any word anywhere" search in a library catalogue or a database, you can type in words that describe your research topic in any order and retrieve records containing those search terms. �A major disadvantage of a keyword search is that it does not take into account the meaning of the words used as search terms, so if a term has more than one meaning (such as "mouse" - computer hardware or rodent? ), irrelevant records may be retrieved.
Think about it �If you knew your person had a red tie, blue shirt, and a green beret, who would be the missing person? What kind of search?
Think about it �This is field searching �Field searching allows you to do a "free-text" search within a specific field, such as author or title. �Words are searched in all fields unless fields are specified. �The fields that are available for searching are a: (author), t: (title), s: (subject), and o: (other), which searches notes, contents, and publishers.
Search techniques �There are basic search techniques that are used when searching for information whether using the library resources, databases or the Internet. �You would have encountered four pieces of information that are needed when you did the catalogue tutorial. These are author, title, subject and keyword.
Search by author �An author search is used to locate works by the author. �The more information about the author you provide, the more limited your search results will be.
Title search �What is a title search?
Title search �A title search is used to locate specific titles of books, references, periodicals and other resources.
Subject search �A subject search is used to find materials on a specific topic
Keyword search �Keyword search is used when the author or title is unknown. This is different from the subject search. �A keyword search looks for specific keywords in all fields whereas the subject search is limited to a specific subject heading.
�Recall vs Precision and Keyword vs Field �When you want to find large amounts of information; general information about a topic, how would you search? �When you want to find small number of sources on a specific topic e. g. for course assignments etc, how would you search?
Search query �Most databases don't understand the natural language we speak and need help understanding what we are looking for. �This requires a special set of conventions
Creating a search query Most databases do not understand the natural language we speak. In this regard, a special set of conventions is utilized when doing a search. These include: Conventions Description Quotation marks Around exact phrases (e. g. “Shortwood college") Logical or Boolean operators Connecting words that narrow or broaden a search to include only what you need. Examples: OR, AND, NOT Wildcards and truncation symbols (* # ? !) For terms that have variant forms of spelling or different possible endings. Examples: child* for child, children, childhood, childish, etc. Using parentheses or Nesting Placing terms in parentheses to indicate separate units. (Like an equation, (A or B) not C
Using quotation marks �Placing double quotation marks (some databases use single around a phrase or single word will restrict a search to that exact word or phrase. quotes) �For example: a search for the term draw will yield results containing that word e. g. drawn, withdrawn, drawing, etc. �A search for “draw” will limit the results to just the word draw.
Boolean operators �Boolean operators were developed by George Boole, an English mathematician in the 19 th century (Gillispie 1970). �The operators are: ■ And ■ Or ■ Not �These commands can be used to widen or narrow a search
Boolean operators � Stringing search terms together using Boolean operators makes searching for various topics easier and more efficient. � Using these operators can greatly reduce or expand the amount of records returned. � Boolean operators are useful in saving time by focusing searches for more 'on-target' results that are more appropriate to your needs, eliminating unsuitable or inappropriate information. � Each search engine or database collection uses Boolean operators in a slightly different way or may require the operator be typed in capitals or have special punctuation.
Boolean operator: AND �The And operator finds the intersection of your ideas. It: narrows your search; and gives fewer, more relevant results Essentially, it increases relevance while decreasing the number of items in your retrieval listing
Boolean operator: AND �The AND operator will return both terms/phrases in the search listing. �Example: A search on stock market AND trading would possibly include the following results: - stock market trading; - trading on the stock market - trading on the late afternoon stock market
Boolean operator: AND �A Venn diagram can be used to illustrate how the AND operator works with two keywords. �The shaded area in the middle is where the two ideas overlap or intersect. �This area represents the records in the database that mention both of the search terms, and these are the only records that will be retrieved.
Boolean operator: AND �When you use the catalogue or database search terms with AND, it returns only those records that have ALL of your search terms, thus reducing the results.
Activity 1: Using the AND operator �You wish to do a search for earthquakes and tsunamis. Use the information below to draw a Venn diagram to indicate the number of results you would possibly obtain from using the AND in your search: �There are 100 articles/records in the database � 24 articles are on tsunamis; 12 of these include earthquakes that follow; 6 on volcanoes; 4 on hurricanes � 22 articles on hurricanes; 15 on tsunamis, earthquakes and hurricanes � 21 articles on volcanic eruptions; 9 include earthquakes �There are 33 articles on earthquakes; 5 include tsunamis
Activity 2: AND operator �If you wanted to search for three terms, earthquakes, tsunamis, hurricanes: �How would you record your search using the AND operator? �Using the previous database information, use a Venn diagram to depict the above search and indicate the possible number of results the search would return.
Boolean operator: OR � The OR operator will return either term in the returned search listing. � The OR operator broadens your search, retrieving more results while decreasing relevance. � Example: A search on ecology OR pollution would possibly include the following results: ─ documents containing the world ecology (but not pollution) and ─ other documents containing the word pollution (but not ecology) as well as ─ documents with ecology and pollution in either order or number of uses
Boolean operator: OR �A Venn diagram can be used to illustrate how the OR operator works with keywords. �When you use OR to combine terms, it broadens your search by having the search engine return at least one of your search terms. �The OR operator is best used when combining synonyms or key words that relate to the same topic, adding comprehensiveness to your search. .
Boolean operator: NOT � The NOT operator disregards those results which contain the word following NOT; i. e. the first term is searched, then any records containing the term after the operators are subtracted from the results. � Example: A search on Mexico NOT city would possibly include the following results: - New Mexico; - the nation of Mexico; - US-Mexico trade; � The search would not return Mexico City or This city's trade relationships with Mexico
Boolean operator: NOT �A Venn diagram can be used to illustrate how the NOT operator works with keywords. � The Not operator excludes ideas from your search, narrowing your results and increases relevance. � When you use NOT operator, it limits your search by excluding all records in which your search term is combined with the unwanted term. � The NOT operator must always be the last Boolean operator you employ.
Activity: Using the quotation or Boolean operators �Visit the Ebscohost database
Sources � Lanning, S. (2012). Concise guide to information literacy. ABC-CLIO, California, USA � What is a Boolean Operator? " Alliant Libraries. Retrieved from http: //library. alliant. edu
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