'Special characters' is the collective name for a group of symbols that are used to communicate properties for a word that has variable spelling or endings. There are several different options for how to handle these types of words. Some common options are
Special characters will differ depending upon the database platform that is being searched.
| Database Platform | Special Character | Functionality |
|---|---|---|
| Engineering Village | " " | Phrase searching |
| * | Unlimited truncation: substitute for zero or more characters in a given character position. | |
| ? | Wildcard: Substitute for a single character in a given position. | |
| $ | Stemming: Specifies position where one or more characters are acceptable. | |
| EBSCOHost | " " | Phrase searching |
| # | Wildcard: Matches one or more characters in a given character position. | |
| ? | Wildcard: Matches exactly one character in a given character position | |
| * | Unlimited truncation or Stemming: substitute for zero or more characters in a given character position. | |
| Scopus | () or " " or {} | Phrase searching: Stemming is automatically conducted with phrase searching |
| * | Wildcard: Matches one or more characters in a given character position | |
| ? | Wildcard: Matches exactly one character in a given character position | |
| Proquest | " " | Phrase search |
| { } | Phrase search with auto stemming | |
| * | Truncation: replaces one or more characters up to 5 | |
| *# | Limited Truncation: replaces one or more characters up to 20 characters. The default is 5 characters | |
| ? | Replace any single character with zero or one other character. It can also be used for stemming at the end of the word. | |
| PubMed | " " | Phrase searching |
| * | Truncation: can be used at the end of a term or phrase to substitute for 0 or more characters. Must be used only with words with at least 4 characters | |
| * | Wildcards can also be used within a word or phrase to substitute for 0 or more characters |
Faceted searching is the use of extensive metadata to create easily engaged filters. Faceted searching is contingent on rich datasets that have identified common attributes that must be present for each record in the database. When a data set is complete, featuring a number of attributes, it allows database designers to create "short cuts" that limit across a given attribute of all the available records. This becomes a fast and efficient method for limiting by a specified aspect of the data that the user is interested in accessing.
Facets vary across databases because the structure of the underlying data is different. Some of this is determined by legacy decisions made to create the database initially (for instance, can you limit by inventor, or is it rolled into an author facet?). In other cases, core datasets are enhanced in order to provide a filter that is desired by end users. (If you see a facet that allows you to narrow by types of Open Access, this is a newer innovation that arose in response to user demand and that required adding additional attributes to records as items are entered into the database.) Facets do not require full text or phrase searching to complete a search and can be used independently. They are frequently used in conjunction with phrase searching and full text searching to winnow down a search set to a manageable level of specificity.
Faceted searching does not require typing syntax in the search. They are "pre-programmed" into the interface, which allows for one or two click addition to the search. The Boolean logic or code for the facet may or may not be recorded in a reproducible manner in the record of the search that was conducted. For instance, it may show the corresponding limiter string in the code, or it may simply have a code that indicates which facet was imposed on the search.
Limiters are specific syntax that can be introduced into a search in order to focus a data set on specific attributes. The syntax of the limiters will change from database to database. The help files for a given database should have a list of the syntax and what effects they have. Limiters have the same effect as facets in many cases and in many cases are shown in the resulting code when facets are selected. However, limiters have the advantage of allowing the end user to control the logic that is used for the limiter with greater precision when entered into the search string directly.
Limiters do require some additional search, whether keyword, phrase searching, or full text searching, in order to create a set across which the limiter can operate. The code for the search is recorded in a reproducible manner in the record of the search that was conducted.
Date searching uses a specific limiter or facet to narrow a search using ISO date syntax. There are some common uses for date searching.
All databases have some form of date searching. Many have multiple variations of the date search, including limiters and faceted searching of date attributes.