Understanding Indexing in Horizon

Horizon uses indexes to quickly retrieve records in your database that match your search results. An index in the Horizon database works conceptually like an index at the end of a book—it contains a word or phrase from the record you are searching for and a link to that record. Indexes make searching for records in your database much faster.

Horizon uses these indexes to build search options in Horizon staff searching. Search options display in the main Search window, and define what type of information you are searching for. (For example, Horizon has a “Title Keyword” search option to search for keywords in titles on the database.)

These are specific types of indexes that are represented as search options:

Keyword index. This type of index lets users enter a keyword that Horizon has indexed from a title field, subject heading fields, content notes field, and so forth. In other words, this type of search finds a match for a keyword by comparing the search terms with a list of words that Horizon has compiled from MARC records or tables in the database. For example, a title keyword search might compare search terms to data stored in all MARC title tags. As another example, a borrower name keyword search in Circulation might compare search terms to data stored in the borrower table.

In addition, you can set up a single search option based on multiple keyword indexes. This lets you search for MARC information that is in either authority-controlled or non-authority controlled subfields. When multiple records match the search term, Horizon displays a list of matches. This type of list is called a “closed” list.

Browse index. This type of search option lets users access an alphabetical list of all titles, authors, subjects, or series in Horizon. The search term that users enter for this type determines which part of the alphabet displays. For this search option, Horizon displays an alphabetical list of record information with the arrow cursor pointing at the entry that most closely matches the search term. (For example, if you did a subject alphabetical search for the word “language,” you would see the first subject heading in the list starting with “language,” and an arrow would point to the closest match. However, you could scroll up and down the alphabetical list and browse through all subject headings on the system.) This type of browsable list is also called an “open” list.
Exact match search. This type of index lets users enter a word or number (such as an LCCN or ISBN) that is directly tied to only one record on the database. (For example, every item in your library will probably have a unique barcode, so when you conduct a barcode search, Horizon immediately displays the bibliographic record without showing a browse list.) In order to get results for an exact match, the user must enter the exact number. Use an exact match index to search for social security numbers, barcodes, and other items for which there is usually one unique match in the database.

This is how Horizon uses indexes and search options when a user does a search in staff searching: The user chooses a search option (such as “Title Browse”) and enters search terms. From the search option, Horizon knows which index to search. This is because part of the search option includes an index definition. The index definition includes the name of the index table where the database stores the indexed data. This database table, powered by a piece of software called an index engine, finds and returns matching bib or authority records for the search and stores that data in the index table. Also from the search option, Horizon knows how the search results display in staff searching. This is because part of the search option definition is also a view definition to control what the search results window looks like. All these processes work together as your staff search for and display search results.

This process is illustrated in these two examples:

 


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