Many commercial online search systems permit the formation complex expressions by using Boolean logic to combine retrieval sets, Boolean logic is algebra of sets. In online information retrieval, Boolean logic is applied to sets of posting. Boolean logic (named after George Boole, a 19th century mathematician) defines logical relationships between terms in a search.

1. BOOLEAN
SEARCH
DR.P.PADMA
ASSISTANT PROFESSOR

2. Introduction
• Many commercial online search
systems permit the formation complex
expressions by using Boolean logic to
combine retrieval sets, Boolean logic is
algebra of sets. In online information
retrieval, Boolean logic is applied to
sets of posting. Boolean logic (named
after George Boole, a 19th century
mathematician) defines logical
relationships between terms in a
search.
• The major Boolean operators are AND,
OR and NOT. If A and B are set of
posting, these Boolean operators have
the following meanings

3. AND
• A and B is set of posting and common to A
AND B, ns is called the intersection of A
and B. A and B represented by expression
A*B on some search systems.
• Use AND to narrow a search. Both terms
must be present in search results. It is often
used for linking together different concepts.
A B OUTPUT
0 0 0
0 1 0
1 0 0
1 1 1

4. OR
• A and B is the et of postings either in
set A of in set B or in both set A and
B, and is called the union of A and B.
A OR B is represented by the
expression A+B on some search
systems
A B OUTPUT
0 0 0
0 1 1
1 0 1
1 1 1

5. NOT
• A NOT B is the set of postings in set
A but not in set B and is called the
difference between A and B. A NOT
B is represented by the expression. A-
B on some search systems. NOT
should be used with cation, since
relevant records can inadvertently be
eliminated with NOT
A OUTPUT
0 1
1 0

6. Boolean
(Truncation and
Wild cards)
• In addition to sing Boolean operators, for
good searches, it may be necessary to use
truncation and wildcard characters to expand
or control searches.
• Truncation allows a search to be conducted
for all the different forms of a word having
the same common root. Truncation is a
searchable shortened form of a word. This
means you can take short cuts. Instead of
writing out adolescents OR adolescence, you
can use the truncated term adolescen*.
• Wild card characters are useful because of
alternate spellings and other quirks in the
English language. Just as British and
Canadian ice cream comes in flavours , not
flavors.

7. Conclusion
• The library and information sector is in
the midst of an era of rapid change.
Developments in technology and the
associated social changes are
presenting new challenges and opening
new possibilities. The available
products are mature in terms of basic
functionality, but the library software
development has entered a volatile,
confusing and yet interesting phase;
the major developments in library
technology now appear to be taking
place in the areas which are outside the
scope of integrated library systems.