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The Adventurer's Guide to Searching the Online Catalog

This document is meant to take you a little bit "under the hood" in the online catalog, to show you some of what makes the catalog work and why it works the way it does. You are also going to learn some of the technical terms that are used to describe different parts of the system.

The Online Catalog

The online catalog for the libraries in C/W MARS is the digital replacement for the old physical card catalog. Large containers filled with drawers and drawers filled with cards have been replaced by centralized collections of electronic information. You no longer have to go into the library to see what materials the library offers. You do not  have to travel to many different libraries to search each one individually. Because information about the materials in the library are now held in one central digital location, you are able to search many libraries simultaneously.

What we think of as the "online catalog" is made up mainly of two things: search interfaces (basic and advanced) for us -- the end users -- to use, and the digital information (data) about everything that the C/W MARS member libraries own that they are choosing to make available.

Sometimes you may hear the online catalog being referred to as "the OPAC" (pronounced "oh-pack"). OPAC is an acronym for "Online Public Access Catalog". Sometimes, "OPAC" is shortened to just "PAC" (pronounced "pack"). If you hear someoe say "Search the PAC", now you know what they're talking about. The online catalog may also be referred to as "the catalog" or "the library catalog".

The search interface is what you see on your screen in your web browser. In C/W MARS, we have a basic search interface, an advanced search interface, and several different interfaces to different kinds of advanced searching. Here's a picture of our Basic Search interface (Basic Search screen):

The internet address for the C/W MARS online catalog is

The search interfaces give human users of the digital information an easy-to-understand way to access that information. (There are non-human "users" of the system. Many different programs perform operations behind the scenes, doing updates, reports, and making scheduled changes. These programs have their own, separate, interfaces to the information.)

The Bibliographic Record

The search interface of the online catalog is a discovery platform. "Discovery Platform" is a technical name for the interface (and all the things you can do with the interface) that you use to search a database. It is common for people to think of the search interfaces as being the online catalog. What the interfaces help you "discover" is the information in the C/W MARS database.

Every item in the online catalog has a bibliographic record (bib record). All the records together are what makes up the bibliographic database that you can search through using the search interfaces.

Together, the search interfaces and the bibliographic records make up the online catalog.

A bib record contains all the information that was entered to help identify and retrieve information about any given item, as well as some additional supporting information.

The data, or information, in a bib record is entered into the database in a special format. A lot of the data in the bibliographic database is indexed for searching. This is just like you would look at the index in the back of a book so that you could find something, except the online catalog can look for many indexes simultaneously.

The main bibliographic data format that we use is called MARC. MARC is an established data format for bibliographic records, used throughout the library and publishing industries.

When the bibliographic information is in MARC format, we call that a MARC record.

All the items in our catalog have MARC records. Some items in the catalog have a lot of information in their MARC record and some do not have a lot.

When you do a search in the online catalog, the catalog searches the information in the bibliographic record to find things that are relevant to your search.

Search Relevance

What is "relevance"?

When you do a search in the online catalog, you enter a keyword or keywords (a word or words that you type into the search box) and  you also have the option of choosing search filters (type of keyword search, type of material, and location).

Relevance refers to the  connection the information in the catalog database and the search string you've entered and the search filters (if any) you've chosen

What makes something "relevant"?

Keywords are a word or words that you enter into the search box on the catalog search screen. These are significant words (like the title of a book or an author's name) that will help finding the items you're looking for in the catalog.

The word (or words) are also called search terms. "Search terms" and "keywords" mean the same thing.

A database record is "relevant" to your keywords because the keywords appear in the record. The more times your keywords appear in a record, the more relevant that database record is considered to be.

How does that work when I do a search?

The catalog database is where all the records are stored of every item owned by every member library.

The database is made up of tables of information and the tables are made up of information fields. An example of a field in a table would be "Title" or "Author". There are many fields in each item's record. Most of the fields are indexed. When a field is indexed, that means the information in the field is available to be searched and found.

Because searching for title and authors is the most popular way of searching the online catalog, when you search for your keywords, the system automatically checks all the records for whether or not your keywords appear in a Title or an Author field.

If your keywords appear in a Title or Author field, the system will show you these results first in the list of search returns. ("Search returns" means the list of items in the catalog that matched your keywords and search filters.)

If your keywords do not appear in a Title or Author field, the system will show you results where your keywords appear in other parts of the records. An example of this might be where a music CD doesn't have the keywords in the Title or Author fields but where the words appear in the name of one of the songs on the album. (Technical note: titles of songs in an album or titles of short stories in a book can also be considered as "titles" from the point of view of the system.)

How do the search filters work with relevance?

A search filter is used to narrow the scope of your search returns. The scope of a search is the area in which a search is appropriate (or "relevant"). In Basic Search, there are three kinds of search filters that can limit the scope of your search returns: a format filter, a Keyword filter, and a Location filter.

When you use one of these filters, your search returns will be limited to records in the database that match the filters.

For example, if you choose "DVD" from the format filters, your search returns will only contain records that have "DVD" in them.

If you choose a particular library, your search returns will only be from items that are owned by that particular library.