Operators

Operators allow you to focus your search by linking search terms and defining the relationship between them. The e-library recognizes the following types of operators.

Some operators take precedence over others when searching the catalog; refer to operator precedence for more information.

In addition, the e-library will not allow you to search for operators when they are at the beginning or end of a search expression and not enclosed in double quotation marks.

Boolean Operators

Boolean operators (AND, NOT, OR, XOR) locate records containing matching terms in one of the specified fields, both of the specified fields, or all of the specified fields. Use Boolean operators to connect words or phrases between more than one text field, or use Boolean operators to connect words or phrases within a text field.

Positional Operators

Positional operators (SAME, WITH, NEAR, ADJ) locate records in which the search terms are in close proximity within the same bibliographical record. Positional operators can be used to connect words or phrases within a search field but not between search fields.

Relational Operators

Relational operators (<, >, =, <>, <=, >=) allow you to search numeral expressions. Use relational operators by enclosing a field name or entry tag number in braces {}, then typing a relational operator and number.

Operator Definition
< less than
> greater than
= equal to
<> not equal to
<= less than or equal to
>= greater than or equal to

For example, if you type "{DATE} < 991022", Unicorn searches for records whose Date field contains values less than 991022.

Operator Precedence

When the search expression consists of a combination of terms, the order in which these terms are searched can be defined. If two operators are at the same level in the list, the e-library first searches the term at the left, then moves right. Refer to the following list for operator precedence, with the highest listed first.

=
<>
<
<=
>
>=
NEAR, ADJ
WITH
SAME
AND, NOT
XOR, OR

Contents

More Searching Tips
Keyword Index Synonyms
Special Characters
Specified Entries
Substitution and Truncation