Online search is the process of interactively searching for and retrieving requested information via a computer from
database
In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and a ...
s that are
online
In computer technology and telecommunications, online indicates a state of connectivity, and offline indicates a disconnected state. In modern terminology, this usually refers to an Internet connection, but (especially when expressed as "on lin ...
.
Interactive searches became possible in the 1980s with the advent of faster databases and smart terminals.
In contrast,
computerized batch searching was prevalent in the 1960s and 1970s.
Today, searches through
web search engine
A search engine is a software system that provides hyperlinks to web pages, and other relevant information on World Wide Web, the Web in response to a user's web query, query. The user enters a query in a web browser or a mobile app, and the sea ...
s constitute the majority of online searches.
Boolean searches
Most
search engine
A search engine is a software system that provides hyperlinks to web pages, and other relevant information on World Wide Web, the Web in response to a user's web query, query. The user enters a query in a web browser or a mobile app, and the sea ...
s offer advanced search options using
Boolean expression
In computer science, a Boolean expression (also known as logical expression) is an expression used in programming languages that produces a Boolean value when evaluated. A Boolean value is either true or false. A Boolean expression may be compos ...
s (also known as Boolean operations). These expressions allow searches to produce more precise and meaningful results.
Based on
Boolean algebra
In mathematics and mathematical logic, Boolean algebra is a branch of algebra. It differs from elementary algebra in two ways. First, the values of the variable (mathematics), variables are the truth values ''true'' and ''false'', usually denot ...
, these types of searches utilize
logical operations using
binary or dyadic processes. These include ''AND'' (
) and OR (
) and the
unary operator
In mathematics, a unary operation is an operation with only one operand, i.e. a single input. This is in contrast to ''binary operations'', which use two operands. An example is any function , where is a set; the function is a unary operatio ...
''NOT'' (
).
The AND and NOT expressions are known as implied Boolean operators as they require or disallow a word or a phrase.
The use of + symbol as a prefix before a keyword requires that word be in a search result. When using multiple Keywords this serves as an AND function requiring that all words with a + sign be in a search result.
The use of - symbol as a prefix before a keyword eliminates that word from search results. This is the NOT Boolean operation
which is sometimes called a negative search.
Searches can not be entirely negative, and must include at least one positive keyword.
Some search engines, such as
google
Google LLC (, ) is an American multinational corporation and technology company focusing on online advertising, search engine technology, cloud computing, computer software, quantum computing, e-commerce, consumer electronics, and artificial ...
, utilize systems with an implied AND operation. This means that the search engine will automatically apply the AND function inbetween keywords without having to enter a symbol for the AND operation.
Other search engines may require that either the symbol &
or +
be added as a prefix before the keyword. These search engines use the "OR" Boolean expression as a default search setting.
Those search engines with a default "AND" expression can still do an "OR" search by using the , symbol inbetween keywords.
References
Internet terminology
Information retrieval genres
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