Online Catalog

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????????Online Catalog
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Whats Online Catalog?

• Online catalogs
• Online Public Access Catalog (OPAC)
• Web-based OPAC (WebPAC)
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• ??????????????? (http//140.113.39.50)
• Issue
• How to create/maintain the contents of OPAC
• The ability to search for bibliographic records
• Simple author or title search
• Complex Boolean, phrase, proximity, range and
  probabilistic search

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Goal

• The purpose of this chapter is to introduce the
  file structures of bibliographic/holding (??/??)
  data that facilitate the search of online catalog
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• ???? The Evolution of Online Cataliog
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• Bridge file structure and RDBMS

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Online Catalog File Structure
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Evolution

• Simple file
• Index file
• Postings file How to handle data with the same
  author, title
• Variable-length bibliographic records capture
  the nature of library data
• Normalization Many copies of a book
• Authority control quality control and assist
  search

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Simple File

• A single file of bibliographic records (????)
• Figure 5.2
• RRN, Author, Title, Publisher, Date
• RRN Relative Record Number
• Fixed-Length records
• Think!! How to add, delete, search
• Is the search process efficient?
• How to improve

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Index File (???)

• For efficient searching and access to records
• Figure 5.3
• Index files are included Author index and Title
  index
• An index entry consists of a KEY and RRN
• In real case, KEY is very complicated
  (concatenation of may author-related fields)
• The index file keeps KEYs in alphabetical order
• Internal structure of an index file may be
  organized into a B-Tree or B - Tree
• How to perform add, delete, and search
• With and without index file

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Postings File (I)

• No two bibliographic records in Figure 5.3 have
  the same author author or title
• For records having the same key
• Hold all RRNs or Ids in an index entry
• How many space is enough
• Another file containing all the Ids
• Postings file is often employed

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Postings File (II)

• Figure 5.4 addresses the problem by a postings
  file
• An index entry has a KEY and a postings file RRN
• A separate postings file
• An postings entry holds the RRNs for records
  having the same KEY, and one pointer to Next
  Posting RRN
• In a real case, a capacity of 25-100 would be
  more realistic
• How to perform add, delete, and search
• Postings file is a useful tool in information
  retrieval and library automation

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MARC (I)

• In general, bibliographic data does not contain a
  fixed number of fields and each field is not a
  fixed length
• Multiple occurrences of a single field
• Multiple subject headings
• Lack certain in one record that present in
  another record
• Uniform title
• Field length may vary wildly
• Fixed-length record (or RDBMS) is not suitable
• The library community developed a standard, MARC,
  to encode and transmit bibliographic data

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MARC (II)

• Identify the contents of records by tagging them
  in accordance with standards
• See Table 5.1 and Figure 5.5
• 245 Title statement
• 100 Personal name
• 650 Subject added entry
• MARC interchange format (ISO2709)
• Figure 5.6
• delimiter to separate fields
• separate sub-fields (e.g. 260)
• _at_ the end of a record

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Variable-Length Bibliographic Record File (I)

• Figure 5.7 (just for example of variable-length
  records)
• The file is viewed as a string of characters
• Each position has a unique number assigned to it
• \n end of the record
• \t separate field
• This scheme relies on the program being able to
  identify the sequence of fields should be author,
  title, publisher, and date.

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Variable-Length Bibliographic Record File (II)

• Figure 5.8 and Figure 5.9
• Each bibliographic record is given a unique
  symbolic identifier
• the bibliographic record identification number
  (bibID)
• How to perform add, delete, and search
• Record length is the issue

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Holding File (I)

• Normalization
• A concept originated from Relational Database
• Eliminate the repetition of the same piece of
  data in multiple tables
• The concept of normalization can be applied in
  Library Automation for a book with multiple
  physical copies
• A librarys collection contains 5 physical copies
  (??) of a book
• Need 5 bibliographic records from Figure 5.1 to
  5.9
• The only difference is likely to be call and copy
  number

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Holding File (II)

• Separate bibliographic information into a
  bibliographic file (???) and a holding file (???)
• Bibliographic file hold information constant
  between copies
• Holding file contain information that differs
• See Figure 5.10
• Bibliographic File RRN, BibID, Holdings File
  RRN, Author, Title
• Holding File RRN, HoldID, NextHoldings RRN, Call
  Number (???), Copy Number (???), Barcode,
  Location (???)

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Holding File (III)

• Advantage
• Save space
• Maintain consistency
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• Disadvantage
• Time
• Complex maintenance
• How to perform add, delete, search

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Authority Control(????)
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Introduction

• Authority Control important for searching as
  well as for bibliographic file maintenance
• Name authority file A list of author names to
• Verify a name in an existing bibliographic
  records matches the spelling of one in the
  authority file
• A source for assigning new names when new
  material is cataloged
• Subject authority file the preferred form of a
  subject or subjects that are broader or narrower
  in scope than others
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Selected MARC Authority Record Tags

• Table 5.2
• 100 Name authority term
• 150 Topical authority term
• 450 Un-authority term designated as
  inappropriate
• 550 broader, narrower, or related term
• Figure 5.11 Figure 5.12 Name authority record
• Figure 5.13 Figure 5.14 Subject authority
  record
• Un-authority term Climbing Mountains, Mountain
  Climbing
• Authority term Mountaineering
• 550 0 w g a Hiking / 550 0 w g Outdoor Life

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Authority Control and Search

• If a search is conducted using an unauthorized
  450 term
• The online catalog can refer the searcher to the
  authorized term
• If a searcher uses the term mountaineering and
  wants to broaden the search
• An authority system can suggest the term hiking

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Authority Control File Structure

• Figure 5.15
• Author, subject and title indexes point to the
  authority index file
• Authority index file
• RRN, Key, Key Type, Bibpost RRN, Authority ID
• How to search for the subject Mountaineering

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Online Catalog with Authority Index and
Cross-References

• The shortcoming of Figure 5.15
• Information intrinsic to the authority records
  themselves is not available for use in searching
  or maintenance activities
• How to perform search when a searcher uses the
  term climbing mountains
• Figure 5.16
• Fields to implement the cross-reference of
  authority file
• Broader, narrower, related, preferred terms
• Point to the cross-reference posting file
• Point back to the authority index file

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Search and Maintenance Operation

• A search for the subject key Arabia
• Subject index ? Authority index (19) ? Cross
  reference postings (15) ? Authority index (5) ?
  Bib postings (5) ? BibID Index (B7) ?
  Bibliographic (2500)
• A search for the subject key Mountaineering
• Subject index ? Authority index (1) ? Bib
  Postings (2) ? BibID Index (B1 and B9) ?
  Bibliographic (0 and 400)
• Broader Subject index ? Authority index (1) ?
  Cross reference postings (2) ? Authority index
  (14 and 15) ? Bib postings file () ? BibID
  Index () ? Bibliographic () In this example,
  no materials are cataloged under the subject
  Hiking and Outdoor life
• Maintenance

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Summary and Review (I)

• File Structure for online catalog systems are
  introduced
• Figure 5.2 Simple bibliographic file
• Figure 5.3 Index files are used to expedite the
  search
• Figure 5.4 Postings files are used for
  one-to-many relationship (Index key searching)
• Figure 5.10 Holding files (the same book with
  many copies)
• Figure 5.15 Authority control
• Figure 5.16 Authority control with cross
  reference

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Summary and Review (II)

• Important files
• Bibliographic, holdings, and postings files
• Index files
• MARC for bibliographic and authority
• Basic steps for searching online catalog
• No authority control
• Index ? (Bib) Posting ? Bibliographic ? Holding
• Authority control
• Index ? Authority Index ? (Cross-Reference)
  Authority Posting ? (Bib) Posting ?
  Bibliographic ? Holding

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Summary and Review (III)

• Basic information recorded in bibliographic file
• RRN (or Unique Bibliographic ID)
• Author, Title
• Publishing information (Publisher, Place, Date)
• Subject
• Basic information recorded in holdings file
• RRN (or Unique Holding ID)
• Call number
• Copy number
• Barcode
• Location

A linking between the bibliographic and holding
files is also necessary
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Summary and Review (IV)

• From file to RDBMS
• How to handle lengthy and variable-length records
• Relationship among tables can be captured by
  foreign keys or another table
• Author/Title index files and RDBMS Index
• Author/Title index files are real tables in RDBMS
• RDBMS Index are created for Author/Title index
  files (tables)
• Postings file may be useful in some case

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Whats Bibliographic Record

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