Indexes: Dynamic Index Fields
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In RavenDB different documents can have different shapes.
Documents are schemaless - new fields can be added or removed as needed. -
For such dynamic data, you can define indexes with dynamic-index-fields.
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This allows querying the index on fields that aren't yet known at index creation time,
which is very useful when working on highly dynamic systems. -
Any value type can be indexed, string, number, date, etc.
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An index definition can contain both dynamic-index-fields and regular-index-fields.
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In this page:
Indexing documents fields KEYS
Example - index any field under object
The following allows you to:
- Index any field that is under the some object from the document.
- After index is deployed, any new field added to the this object will be indexed as well.
The document:
public class Product {
private String id;
// The KEYS under the attributes object will be dynamically indexed
// Fields added to this object after index creation time will also get indexed
private Dictionary<String, Object> attributes;
// get + set implementation ...
}
// Sample document content
{
"attributes": {
"color": "Red",
"size": 42
}
}
The index:
-
The following index will index any field under the
attributes
object from the document,
a dynamic-index-field will be created for each such field.
New fields added to the object after index creation time will be dynamically indexed as well. -
The actual dynamic-index-field name on which you can query will be the attribute field key.
e.g. Keyscolor
&size
will become the actual dynamic-index-fields.
public class Products_ByAttributeKey_JS extends AbstractJavaScriptIndexCreationTask {
public Products_ByAttributeKey_JS() {
// Call 'createField' to generate dynamic-index-fields from the attributes object keys
// Using '_' is just a convention. Any other string can be used instead of '_'
// The actual field name will be the key
// The actual field terms will be derived from p.attributes[key]
setMaps(Sets.newHashSet(
"map('Products', function (p) { " +
" return { " +
" _: Object.keys(p.attributes).map(key => createField(key, p.attributes[key], " +
" { indexing: 'Search', storage: false, termVector: null })) " +
" }; " +
"}) "
));
}
}
The query:
-
You can now query the generated dynamic-index fields.
Property_
is Not queryable, it is only used in the index definition syntax. -
To get all documents with some 'size' use:
List<Product> matchingDocuments = session
.query(Product.class, Products_ByAttributeKey_JS.class)
.whereEquals("size", 42)
.toList();
// 'size' is a dynamic-index-field that was indexed from the Attributes object
from index 'Products/ByAttributeKey/JS' where size = 42
Example - index any field
The following allows you to:
- Define an index on a collection without needing any common structure between the indexed documents.
- After index is deployed, any new field added to the document will be indexed as well.
Consider if that is a true necessity, as indexing every single field can end up costing time and disk space.
The document:
public class Product {
private String id;
// All KEYS in the document will be dynamically indexed
// Fields added to the document after index creation time will also get indexed
private String firstName;
private String lastName;
private String title;
// ...
// get + set implementation ...
}
// Sample document content
{
"firstName": "John",
"lastName": "Doe",
"title": "Engineer",
// ...
}
The index:
-
The following index will index any field from the document,
a dynamic-index-field will be created for each field.
New fields added to the document after index creation time will be dynamically indexed as well. -
The actual dynamic-index-field name on which you can query will be the field key.
e.g. KeysfirstName
&lastName
will become the actual dynamic-index-fields.
public class Products_ByAnyField_JS extends AbstractJavaScriptIndexCreationTask {
public Products_ByAnyField_JS() {
// This will index EVERY FIELD under the top level of the document
setMaps(Sets.newHashSet(
"map('Products', function (p) { " +
" return { " +
" _: Object.keys(p).map(key => createField(key, p[key], " +
" { indexing: 'Search', storage: true, termVector: null })) " +
" }; " +
"}) "
));
}
}
The query:
- To get all documents with some 'lastName' use:
List<Product> matchingDocuments = session
.query(Product.class, Products_ByAnyField_JS.class)
.whereEquals("lastName", "Doe")
.toList();
// 'lastName' is a dynamic-index-field that was indexed from the document
from index 'Products/ByAnyField/JS' where lastName = "Doe"
Indexing documents fields VALUES
Example - basic
This example shows:
- Only the basic concept of creating a dynamic-index-field from the value of a document field.
- Documents can then be queried based on those indexed values.
- For a more practical usage see the Example below.
The document:
public class Product {
private String id;
// The VALUE of productType will be dynamically indexed
private String productType;
private int pricePerUnit;
// get + set implementation ...
}
// Sample document content
{
"productType": "Electronics",
"pricePerUnit": 23
}
The index:
-
The following index will index the value of document field 'productType'.
-
This value will be the dynamic-index-field name on which you can query.
e.g. Field valueElectronics
will be the dynamic-index-field.
public class Products_ByProductType extends AbstractIndexCreationTask {
public Products_ByProductType() {
// The field name will be the value of document field 'productType'
// The field terms will be derived from document field 'pricePerUnit'
map = "docs.Products.Select(p => new { " +
" _ = this.CreateField(p.productType, p.pricePerUnit) " +
"})";
}
}
The query:
- To get all documents of some product type having a specific price per unit use:
List<Product> matchingDocuments = session
.query(Product.class, Products_ByProductType.class)
.whereEquals("Electronics", 23)
.toList();
// 'Electronics' is the dynamic-index-field that was indexed from document field 'productType'
from index 'Products/ByProductType' where Electronics = 23
Example - list
The following allows you to:
- Index values from items in a list
- After index is deployed, any item added this list in the document will be dynamically indexed as well.
The document:
public class Product {
private String id;
private String name;
// For each element in this list, the VALUE of property 'propName' will be dynamically indexed
// e.g. Color, Width, Length (in ex. below) will become dynamic-index-fields
private List<Attribute> attributes;
// get + set implementation ...
}
public class Attribute {
private String propName;
private String propValue;
// get + set implementation ...
}
// Sample document content
{
"name": "SomeName",
"attributes": [
{
"propName": "Color",
"propValue": "Blue"
},
{
"propName": "Width",
"propValue": "10"
},
{
"propName": "Length",
"propValue": "20"
},
...
]
}
The index:
-
The following index will create a dynamic-index-field per item in the document's
attributes
list.
New items added to the attributes list after index creation time will be dynamically indexed as well. -
The actual dynamic-index-field name on which you can query will be the item's propName value.
e.g. 'propName' valueWidth
will be a dynamic-index-field.
public class Attributes_ByName extends AbstractIndexCreationTask {
public Attributes_ByName() {
// For each attribute item, the field name will be the value of field 'propName'
// The field terms will be derived from field 'propValue'
// A regular-index-field (Name) is defined as well
map =
"docs.Products.Select(p => new { " +
" _ = p.attributes.Select(item => this.CreateField(item.propName, item.propValue)), " +
" Name = p.name " +
"})";
}
}
The query:
- To get all documents matching a specific attribute property use:
List<Product> matchingDocuments = session
.query(Product.class, Attributes_ByName.class)
.whereEquals("Width", 10)
.toList();
// 'Width' is a dynamic-index-field that was indexed from the attributes list
from index 'Attributes/ByName' where Width = 10
CreateField syntax
Syntax for LINQ-index:
object CreateField(string name, object value);
object CreateField(string name, object value, bool stored, bool analyzed);
object CreateField(string name, object value, CreateFieldOptions options);
Syntax for JavaScript-index:
createField(fieldName, fieldValue, options); // returns object
Parameters | ||
---|---|---|
fieldName | string |
Name of the dynamic-index-field |
fieldValue | object |
Value of the dynamic-index-field The field Terms are derived from this value. |
stored | bool |
Sets FieldStoragefalse - will set FieldStorage.No (default value)true - will set FieldStorate.Yes |
analyzed | bool |
Sets FieldIndexingnull - FieldIndexing.Default (default value)false - FieldIndexing.Exact true - FieldIndexing.Search |
options | CreateFieldOptions |
Dynamic-index-field options |
CreateFieldOptions | ||
---|---|---|
Storage | FieldStorage? |
Learn about storing data in the index. |
Indexing | FieldIndexing? |
Learn about using analyzers in the index. |
TermVector | FieldTermVector? |
Learn about term vectors in the index. |
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All above examples have used the character
_
in the dynamic-index-field definition.
However, using_
is just a convention. Any other string can be used instead. -
This property is Not queryable, it is only used in the index definition syntax.
The actual dynamic-index-fields that are generated are defined by theCreateField
method.
Indexed fields & terms view
The generated dynamic-index-fields and their indexed terms can be viewed in the Terms View.
Below are sample index fields & their terms generated from the last example.
Figure-1: Go to Terms View
Figure-2: Indexed fields & terms