def index_of(field: FieldRef, *, prefix: str | None = None) -> IndexObject

def index_of(memo_type: type, field_name: str, *, prefix: str | None = None) -> IndexObject

Return the managed query index for an indexed memo field.

The preferred form passes a field reference from db0.fields_of(...):

priority = db0.index_of(db0.fields_of(Task).priority)

The string form is also supported:

priority = db0.index_of(Task, "priority")

Parameters

• field FieldRef
  A field reference returned by db0.fields_of(Type).field or db0.fields_of(Type)["field"].

• memo_type type
  A dbzero memo type.

• field_name str
  Name of an indexed field on memo_type.

• prefix str, optional
  Prefix to resolve the managed index in. If omitted, dbzero uses the current prefix, or the fixed prefix for a scoped memo type.

Returns

An IndexObject sealed for query use.

Examples

@db0.indexed_fields("priority")
@db0.memo
class Task:
    def __init__(self, title, priority):
        self.title = title
        self.priority = priority
 
Task("Fix outage", 1)
Task("Update docs", 4)
 
priority = db0.index_of(db0.fields_of(Task).priority)
urgent = db0.find(Task, priority.select(1, 2))
ordered = priority.sort(db0.find(Task))

Use subscription for dynamic field names:

field_name = "priority"
priority = db0.index_of(db0.fields_of(Task)[field_name])

Managed Index Operations

The returned index supports query operations:

• select(low=None, high=None, null_first=False)
• sort(query, desc=False, null_first=False)
• len(index)

Mutation operations are rejected because dbzero owns the managed index:

• add(...)
• remove(...)
• clear()
• flush()

Errors

db0.index_of(...) raises an error when:

• the type is not a memo type
• the field name is unknown or not declared with @db0.indexed_fields(...)
• a FieldRef is combined with a separate field_name
• an explicit prefix conflicts with a fixed-prefix memo type
• the caller does not have read access to a protected field

See Indexed Fields for migration and design guidance.