Core Types

Each JSON field can be mapped to a specific core type. JSON itself already provides us with some typing, with its support for string, integer/long, float/double, boolean, and null.

The following sample tweet JSON document will be used to explain the core types:

{
    "tweet" {
        "user" : "kimchy"
        "message" : "This is a tweet!",
        "postDate" : "2009-11-15T14:12:12",
        "priority" : 4,
        "rank" : 12.3
    }
}

Explicit mapping for the above JSON tweet can be:

{
    "tweet" : {
        "properties" : {
            "user" : {"type" : "string", "index" : "not_analyzed"},
            "message" : {"type" : "string", "null_value" : "na"},
            "postDate" : {"type" : "date"},
            "priority" : {"type" : "integer"},
            "rank" : {"type" : "float"}
        }
    }
}

String

The text based string type is the most basic type, and contains one or more characters. An example mapping can be:

{
    "tweet" : {
        "properties" : {
            "message" : {
                "type" : "string",
                "store" : "yes",
                "index" : "analyzed",
                "null_value" : "na"
            }
        }
    }
}

The above mapping defines a string message property/field within the tweet type. The field is stored in the index (so it can later be retrieved using selective loading when searching), and it gets analyzed (broken down into searchable terms). If the message has a null value, then then value that will be stored is na.

The following table lists all the attributes that can be used with the string type:

Attribute	Description
index_name	The name of the field that will be stored in the index. Defaults to the property/field name.
store	Set to yes the store actual field in the index, no to not store it. Defaults to no (note, the JSON document itself is stored, and it can be retrieved from it).
index	Set to analyzed for the field to be indexed and searchable after being broken down into token using an analyzer. not_analyzed means that its still searchable, but does not go through any analysis process or broken down into tokens. no means that it won’t be searchable at all (as an individual field; it may still be included in _all). Defaults to analyzed.
term_vector	Possible values are no, yes, with_offsets, with_positions, with_positions_offsets. Defaults to no.
boost	The boost value. Defaults to 1.0.
null_value	When there is a (JSON) null value for the field, use the null_value as the field value. Defaults to not adding the field at all.
omit_norms	Boolean value if norms should be omitted or not. Defaults to false.
omit_term_freq_and_positions	Boolean value if term freq and positions should be omitted. Defaults to false.
analyzer	The analyzer used to analyze the text contents when analyzed during indexing and when searching using a query string. Defaults to the globally configured analyzer.
index_analyzer	The analyzer used to analyze the text contents when analyzed during indexing.
search_analyzer	The analyzer used to analyze the field when part of a query string.
include_in_all	Should the field be included in the _all field (if enabled). Defaults to true or to the parent object type setting.

The string type also support custom indexing parameters associated with the indexed value. For example:

{
    "message" : {
        "_value":  "boosted value",
        "_boost":  2.0
    }
}

The mapping is required to disambiguate the meaning of the document. Otherwise, the structure would interpret “message” as a value of type “object”. The key _value (or value) in the inner document specifies the real string content that should eventually be indexed. The _boost (or boost) key specifies the per field document boost (here 2.0).

Number

A number based type supporting float, double, byte, short, integer, and long. It uses specific constructs within Lucene is order to support numeric values. An example mapping can be:

{
    "tweet" : {
        "properties" : {
            "rank" : {
                "type" : "float",
                "null_value" : 1.0
            }
        }
    }
}

The following table lists all the attributes that can be used with a numbered type:

Attribute	Description
type	The type of the number. Can be float, double, integer, long, short, byte. Required.
index_name	The name of the field that will be stored in the index. Defaults to the property/field name.
store	Set to yes the store actual field in the index, no to not store it. Defaults to no (note, the JSON document itself is stored, and it can be retrieved from it).
index	Set to no if the value should not be indexed. In this case, store should be set to yes, since if its not indexed and not stored, there is nothing to do with it.
precision_step	The precision step (number of terms generated for each number value). Defaults to 4.
boost	The boost value. Defaults to 1.0.
null_value	When there is a (JSON) null value for the field, use the null_value as the field value. Defaults to not adding the field at all.
include_in_all	Should the field be included in the _all field (if enabled). Defaults to true or to the parent object type setting.

Date

The date type is a special type which maps to JSON string type. It follows a specific format that can be explicitly set. All dates are UTC. as. Internally, a date maps to a number type long, with the added parsing stage from string to long and from long to string. An example mapping:

{
    "tweet" : {
        "properties" : {
            "postDate" : {
                "type" : "date",
                "format" : "YYYY-MM-dd"
            }
        }
    }
}

The date type will also accept a long number representing UTC milliseconds since the epoch, regardless of the format it can handle.

The following table lists all the attributes that can be used with a date type:

Attribute	Description
index_name	The name of the field that will be stored in the index. Defaults to the property/field name.
format	The date format. rence-mapping-date-format>`. Defaults to dateOptionalTime.
store	Set to yes the store actual field in the index, no to not store it. Defaults to no (note, the JSON document itself is stored, and it can be retrieved from it).
index	Set to no if the value should not be indexed. In this case, store should be set to yes, since if its not indexed and not stored, there is nothing to do with it.
precision_step	The precision step (number of terms generated for each number value). Defaults to 4.
boost	The boost value. Defaults to 1.0.
null_value	When there is a (JSON) null value for the field, use the null_value as the field value. Defaults to not adding the field at all.
include_in_all	Should the field be included in the _all field (if enabled). Defaults to true or to the parent object type setting.

Boolean

The boolean type Maps to the JSON boolean type. It ends up storing within the index either T or F, with automatic translation to true and false respectively.

{
    "tweet" : {
        "properties" : {
            "hes_my_special_tweet" : {
                "type" : "boolean",
            }
        }
    }
}

The boolean type also supports passing the value as a number (in this case 0 is false, all other values are true).

The following table lists all the attributes that can be used with the boolean type:

Attribute	Description
index_name	The name of the field that will be stored in the index. Defaults to the property/field name.
store	Set to yes the store actual field in the index, no to not store it. Defaults to no (note, the JSON document itself is stored, and it can be retrieved from it).
index	Set to no if the value should not be indexed. In this case, store should be set to yes, since if its not indexed and not stored, there is nothing to do with it.
boost	The boost value. Defaults to 1.0.
null_value	When there is a (JSON) null value for the field, use the null_value as the field value. Defaults to not adding the field at all.
include_in_all	Should the field be included in the _all field (if enabled). Defaults to true or to the parent object type setting.

Binary

The binary type is a base64 representation of binary data that can be stored in the index. The field is always stored and not indexed at all.

{
    "tweet" : {
        "properties" : {
            "image" : {
                "type" : "binary",
            }
        }
    }
}

The following table lists all the attributes that can be used with the binary type:

Attribute	Description
index_name	The name of the field that will be stored in the index. Defaults to the property/field name.