The search is as follows:
- The searcher defines the search criteria and other parameters for controlling the function.
- A procedure is used to compare the database with the search criteria.
- The first or all or the first N hits of the data set that match the search criteria are used.
Example phone book
An example from everyday life is the phone book . The method used is the index-sequential search.
- First, open the first letter of the name you are looking for using the tabs at the edge of the telephone book ( index ).
- Then the following pages are run through individually ( sequentially ) until the name you are looking for is found.
- Since the phone book is sorted by surname and first name, the search can be further accelerated by e.g. For example, you can always scroll 5 pages and then compare whether the second letter of the last name matches. If it is smaller, you jump back a few pages. Otherwise you either jump on or continue with the sequential search.
Search functions in computer programs
Convenient search functions are very often available in computer programs, which enable a quick (duration of a few seconds) search of huge data stocks (billions of data records). Sorting and indexing of the data is an essential requirement for a quick search . The development and implementation of search algorithms is a branch of computer science .
The range of functions of frequently used search functions ranges from very simple with a simple text editor (e.g. Notepad.exe in MS Windows) to detailed (e.g. grep program) to very complex ( SQL databases).
The availability of a needs-based search function is the basic requirement for the meaningful use of programs today. The absence of a search function is a limitation that suggests using another product with a similar function that provides a search function. Even a simple search function results in a noticeable increase in productivity when working with the application.
Intelligent search function
The measure of the intelligence of the function is the ratio of the effort required to enter search criteria to the accuracy of the hit achieved while maintaining the acceptable time after which the first search result should be available. For example, after a few seconds when a single keyword is entered , an Internet search engine should return the address of the Internet pages that have the maximum reference to this keyword, sorted in descending order of relevance. Typing or spelling errors must be recognized automatically and suggestions for corrections made if necessary. Entering search criteria using a certain syntax is only acceptable to a very limited extent. Products with an 'intelligent' search function have been very successful in the recent past.
Complex search function
With complex search functions, the effort for entering the search criteria plays a subordinate role. It is carried out by trained experts and can include And take many days. To do this, it is almost always necessary to learn the extensive syntax of a specialized query language. The focus is on the precision of the search results, the speed and the consumption of resources . It should be possible to obtain additional information during the implementation, e.g. B. statistical data. A search run should be able to search for several criteria at the same time. Complex search functions have to deal with huge amounts of data, e.g. B. Billions of files or databases with several terabytes in size.