The FieldInfo object is a vector of field entries from the Solr
schema. Typically, one retrieves an instance with fields
and shows it on the console to get an overview of the schema. The
vector-like nature means that functions like [ and
length behave as expected.
These functions get the “columns” from the field information “table”:
name(x): Gets the name of the field.
typeName(x): Gets the name of the field type, see
fieldTypes.
dynamic(x): Gets whether the field is dynamic, i.e.,
whether its name is treated as a wildcard glob. If a document
field does not match a static field name, it takes its
properties from the first dynamic field (in schema order) that it
matches.
multiValued(x): Gets whether the field accepts multiple
values. A multi-valued field is manifested in R as a list.
required(x): Gets whether the field must have a value in
every document. A non-required field will sometimes have NAs. This
is useful for both ensuring data integrity and optimizations.
indexed(x): Gets whether the field has been indexed. A
field must be indexed for us to filter by it. Faceting requires a
field to be indexed or have doc values.
stored(x): Gets whether the data for a field have been
stored in the database. We can search on any (indexed) field, but
we can only retrieve data from stored fields.
docValues(x): Gets whether the data have been additionally
stored in a columnar format that accelerates Solr function calls
(transform) and faceting (aggregate).
x %in% table: Returns whether each field name in x
matches a field defined in table, a FieldInfo
object. This convenience is particularly needed when the schema
contains dynamic fields.