Important concepts and terms

In order to work with EQL, you need to understand the following concepts.

• Attribute: An attribute is the basic unit of a record schema. Attributes describe records in the Endeca Server.
  • Single-assign attribute: An attribute for which a record may have only one value. For example, because a book has only one price, the Price attribute would be single-assign. Single-assign attributes are of the atomic data type (such as mdex:string and mdex:double).
  • Multi-assign attribute: An attribute for which a record may have more than one value. For example, because a book may have more than one author, the Author attribute would be multi-assign. Multi-assign attributes are of the set data type (such as mdex:string-set and mdex:double-set). They are represented in EQL by sets (see Sets and Multi-assign Data).
  • Managed attribute: An attribute for which a hierarchy of attribute values is attached. Managed attributes are used to support hierarchical navigation.
  • Standard attribute: An attribute whose value is not included in an enumerated list or hierarchy.
• Record: The fundamental unit of data in the Endeca Server. Records are assigned attribute values. An assignment indicates that a record has a value for an attribute. A record typically has assignments from multiple attributes. Records in the corpus can include multiple assignments to the same attribute, as can records in EQL results.
• Corpus: The full body of Endeca Server records. Endeca Server data is corpus–based rather than table–based. By default, the source of records for an EQL statement is the result of the containing search and navigation query. However, you can also include the FROM syntax in your statement to specify a different record source, such as from the corpus, from a previously-defined statement, or from a named state. Two names identify a corpus-based source:
  • AllBaseRecords: Every record that passed the security filter.
  • NavStateRecords: Every record that passed all previous filters.

  The omission of the FROM clause implies FROM NavStateRecords. This implicit FROM is equivalent to using a WHERE clause that expresses the filters currently applied.

• Statement: A unit of EQL that computes related or independent analytics results. In EQL, a statement starts with DEFINE or RETURN and ends with a semi-colon if it is between statements (the semi-colon is optional on the last statement). The statement also includes a mandatory SELECT clause and, optionally, some other clause(s).
• Result: Query results are a collection of statement results; statement results are a collection of records.
  • Intermediate results: Results from RETURN statements can also be used as intermediate results for further processing by other statements.
  • Returned results: Set of matching values returned by the query or statement.
• Query: A request sent to the Endeca Server. In general, a query consists of multiple statements.