Module tantivy::schema

Schema definition for tantivy's indices.

Setting your schema in Tantivy

Tantivy has a very strict schema. The schema defines information about the fields your index contains, that is, for each field:

• the field name (may only contain letters [a-zA-Z], number [0-9], and _)
• the type of the field (currently only text and u64 are supported)
• how the field should be indexed / stored.

This very last point is critical as it will enable / disable some of the functionality for your index.

Tantivy's schema is stored within the meta.json file at the root of your directory.

Building a schema "programmatically"

Setting a text field

Example

use tantivy::schema::*;
let mut schema_builder = Schema::builder();
let title_options = TextOptions::default()
    .set_stored()
    .set_indexing_options(TextFieldIndexing::default()
        .set_tokenizer("default")
        .set_index_option(IndexRecordOption::WithFreqsAndPositions));
schema_builder.add_text_field("title", title_options);
let schema = schema_builder.build();

We can split the problem of generating a search result page into two phases :

• identifying the list of 10 or so documents to be displayed (Conceptually query -> doc_ids[])
• for each of these documents, retrieving the information required to generate the search results page. (doc_ids[] -> Document[])

In the first phase, the ability to search for documents by the given field is determined by the TextIndexingOptions of our TextOptions.

The effect of each possible setting is described more in detail TextIndexingOptions.

On the other hand setting the field as stored or not determines whether the field should be returned when searcher.doc(doc_address) is called.

Setting a u64, a i64 or a f64 field

Example

use tantivy::schema::*;
let mut schema_builder = Schema::builder();
let num_stars_options = IntOptions::default()
    .set_stored()
    .set_indexed();
schema_builder.add_u64_field("num_stars", num_stars_options);
let schema = schema_builder.build();

Just like for Text fields (see above), setting the field as stored defines whether the field will be returned when searcher.doc(doc_address) is called, and setting the field as indexed means that we will be able perform queries such as num_stars:10. Note that unlike text fields, u64 can only be indexed in one way for the moment. This may change when we will start supporting range queries.

The fast option on the other hand is specific to u64 fields, and is only relevant if you are implementing your own queries. This functionality is somewhat similar to Lucene's DocValues.

u64 that are indexed as fast will be stored in a special data structure that will make it possible to access the u64 value given the doc id rapidly. This is useful if the value of the field is required during scoring or collection for instance.

Shortcuts

For convenience, it is possible to define your field indexing options by combining different flags using the | operator.

For instance, a schema containing the two fields defined in the example above could be rewritten :

use tantivy::schema::*;
let mut schema_builder = Schema::builder();
schema_builder.add_u64_field("num_stars", INDEXED | STORED);
schema_builder.add_text_field("title", TEXT | STORED);
let schema = schema_builder.build();

Structs

Document	Tantivy's Document is the object that can be indexed and then searched for.
Facet	A Facet represent a point in a given hierarchy.
Field	Field is actually a u8 identifying a Field The schema is in charge of holding mapping between field names to Field objects.
FieldEntry	A FieldEntry represents a field and its configuration. Schema are a collection of FieldEntry
FieldValue	FieldValue holds together a Field and its Value.
IntOptions	Define how an int field should be handled by tantivy.
NamedFieldDocument	Internal representation of a document used for JSON serialization.
Schema	Tantivy has a very strict schema. You need to specify in advance, whether a field is indexed or not, stored or not, and RAM-based or not.
SchemaBuilder	Tantivy has a very strict schema. You need to specify in advance whether a field is indexed or not, stored or not, and RAM-based or not.
Term	Term represents the value that the token can take.
TextFieldIndexing	Configuration defining indexing for a text field.
TextOptions	Define how a text field should be handled by tantivy.

Enums

Cardinality	Express whether a field is single-value or multi-valued.
DocParsingError	Error that may happen when deserializing a document from JSON.
FieldType	A FieldType describes the type (text, u64) of a field as well as how it should be handled by tantivy.
IndexRecordOption	IndexRecordOption describes an amount information associated to a given indexed field.
Type	Type of the value that a field can take.
Value	Value represents the value of a any field. It is an enum over all over all of the possible field type.

Constants

FAST	Flag to mark the field as a fast field (similar to Lucene's DocValues)
INDEXED	Flag to mark the field as indexed.
STORED	Flag to mark the field as stored. This flag can apply to any kind of field.
STRING	The field will be untokenized and indexed
TEXT	The field will be tokenized and indexed

Functions

is_valid_field_name

Validator for a potential field_name. Returns true iff the name can be use for a field name.