---
name: "Lucy::Plan::Schema"
section: "3pm"
platform: "linux"
package: "liblucy-perl"
version: "0.3.3-7+b1"
release: "Debian 9 (Stretch)"
platforms: ["linux"]
url: "https://new.carta.tech/Lucy::Plan::Schema"
---

# Lucy::Plan::Schema(3pm)

User-created specification for an inverted index.

## NAME

Lucy::Plan::Schema - User-created specification for an inverted index.

## SYNOPSIS

```
    use Lucy::Plan::Schema;
    use Lucy::Plan::FullTextType;
    use Lucy::Analysis::PolyAnalyzer;

    my $schema = Lucy::Plan::Schema->new;
    my $polyanalyzer = Lucy::Analysis::PolyAnalyzer->new(
        language => 'en',
    );
    my $type = Lucy::Plan::FullTextType->new(
        analyzer => $polyanalyzer,
    );
    $schema->spec_field( name => 'title',   type => $type );
    $schema->spec_field( name => 'content', type => $type );
```

## DESCRIPTION

A Schema is a specification which indicates how other entities should interpret the raw data in an inverted index and interact with it.

Once an actual index has been created using a particular Schema, existing field definitions may not be changed.  However, it is possible to add new fields during subsequent indexing sessions.

## CONSTRUCTORS

### *new()*

```
    my $schema = Lucy::Plan::Schema->new;
```

Constructor.  Takes no arguments.

## METHODS

### spec\_field( *\[labeled params\]* )

Define the behavior of a field by associating it with a FieldType.

If this method has already been called for the supplied `"field"`, it will merely test to verify that the supplied FieldType *equals()* the existing one.

- •

  **name** - The name of the field.

- •

  **type** - A FieldType.

### *num\_fields()*

Return the number of fields currently defined.

### *all\_fields()*

Return all the Schema's field names as an array.

### fetch\_type(field)

Return the FieldType for the specified field.  If the field can't be found, return undef.

### fetch\_sim(field)

Return the Similarity for the specified field, or undef if either the field can't be found or it isn't associated with a Similarity.

### *architecture()*

Factory method which creates an Architecture object for this index.

### *get\_architecture()*

Return the Schema instance's internal Architecture object.

### *get\_similarity()*

Return the Schema instance's internal Similarity object.

## INHERITANCE

Lucy::Plan::Schema isa Lucy::Object::Obj.