OData (Open Data Protocol) is a REST-based protocol for querying and updating data using simple HTTP messages. It is an OASIS standard based on technologies such as HTTP, Atom/XML and JSON.
Denodo OData Service allows Denodo users to connect to the Denodo Platform and query its databases using an OData 2.0 interface.
Note that this document will use <VERSION> as a placeholder for the specific version of the Denodo Platform you are installing the Denodo OData Service for. So this placeholder should be replaced by the Denodo version number of your installation.
The Denodo OData Service distribution consists of:
For running the Denodo OData Service you need to deploy the war file in Apache Tomcat 7+ (using Java 7 or later). You need to include the Virtual DataPort (VDP) driver in the folder /lib of Apache Tomcat 7+.
VDP driver (denodo-vdp-jdbcdriver.jar) is in the folder:
The web application container must provide the data source configuration in order to connect to the Denodo Virtual DataPort server using JNDI. The JNDI name of the resource must be jdbc/VDPdatabase. See the Configuring JNDI resources in Apache Tomcat for more information.
The Denodo OData service has some properties:
For example, being: odataserver.serviceRoot=https://gw.denodo.com:9000/ODATA/ and accessing: http://server001:9090/denodo-odata2-service-<VERSION>/denodo-odata.svc/movies will return this kind of URI within the response: https://gw.denodo.com:9000/ODATA/denodo-odata.svc/movies |
The war file includes a configuration file WEB-INF/classes/configuration.properties that has default values for the properties explained above:
odataserver.address=/denodo-odata.svc odataserver.serviceRoot= server.pageSize=1000 enable.adminUser=true debug.enabled=false |
Besides, these properties can be provided by the web container via JNDI (see the Configuring JNDI resources in Apache Tomcat section for more information).
Properties configured at the web container as JNDI entries have higher precedence than those established at the configuration.properties file.
Once you deploy the war you can use the Denodo OData Service from a web client, using HTTP Basic Authentication with VDP-valid credentials. Therefore you may use URLs that are of the form:
http://localhost:8080/denodo-odata.svc/<DBNAME>
Note that for the sake of simplicity in this document, we will consider the OData server to be installed at the ROOT context of the web server.
For deploying the service in the internal web container of the Denodo Platform you have two options:
You should follow these steps:
file that the common.loader property (shared.loader in Denodo 5.5) includes a reference to the VDP JDBC Driver.
If missing, add it:
Make sure to modify the DENODO_HOME variable in the script templates to point to your Denodo installation.
http://localhost:9090/denodo-odata2-service-<VERSION>/denodo-odata.svc/<DBNAME>
This option is only for Windows systems.
After launching of the service you can navigate to:
http://localhost:9090/denodo-odata2-service-<VERSION>/denodo-odata.svc/<DBNAME>
If you deploy the Denodo OData Service into the Denodo embedded web container you must declare the JNDI resource in:
<DENODO_HOME>/resources/apache-tomcat/conf/server.xml file
Below, there is an example:
<GlobalNamingResources> <Resource name="jdbc/VDPdatabase" auth="Container" type="javax.sql.DataSource" username="admin" password="admin" url="jdbc:vdb://localhost:9999/admin" driverClassName="com.denodo.vdp.jdbc.Driver" initialSize="5" maxWaitMillis="5000" maxTotal="20" maxIdle="5" validationQuery="select 1" poolPreparedStatements="true"/> </GlobalNamingResources> |
If you deploy the Denodo OData service into the Denodo embedded web container the context.xml file is in the <DENODO_HOME>/resources/apache-tomcat/conf folder.
<Context> <ResourceLink name="jdbc/VDPdatabase" global="jdbc/VDPdatabase" type="javax.sql.DataSource"/> </Context> |
If you deploy the Denodo OData Service into the Denodo embedded web container you must declare the JNDI resource in:
<DENODO_HOME>/resources/apache-tomcat/conf/context.xml file
<Context> <Resource name="jdbc/VDPdatabase" auth="Container" type="javax.sql.DataSource" username="admin" password="admin" url="jdbc:vdb://localhost:9999/admin" driverClassName="com.denodo.vdp.jdbc.Driver" initialSize="5" <!-- maxWaitMillis and maxWait for --> <!-- compatibility between Tomcat versions --> maxWaitMillis="5000" maxWait="5000" <!-- maxTotal and maxActive for compatibility --> <!-- between Tomcat versions --> maxTotal="20" maxActive="20" maxIdle="5" minIdle="0" validationQuery="select 1" poolPreparedStatements="true"/> </Context> |
* The settings described for Denodo Platform 6.0 can work with 5.5 but in the initialization of Tomcat embedded would appear a spurious error that you could ignore.
* The parameter minIdle could be greater than 0. In this way the performance of the connections would be better, but other applications could maintain open connections that never will be used.
Declare the properties values in the context.xml file:
<Context> <Environment type="java.lang.String" name="odataserver.address" value="/denodo-odata.svc"/> <Environment type="java.lang.String" name="odataserver.serviceRoot" value=""/> <!-- OPTIONAL PARAMETER --> <Environment type="java.lang.Integer" name="server.pageSize" value="1000"/> <Environment type="java.lang.Boolean" name="enable.adminUser" value="false"/> <Environment type="java.lang.Boolean" name="debug.enabled" value="false"/> </Context> |
If you deploy the service in the internal web container of the Denodo Platform, this file is at <DENODO_HOME>/resources/apache-tomcat/conf.
Users of OData Service should have the following VDP privileges assigned:
Denodo OData Service provides the following main features:
There are two types of metadata documents:
It is available at the root URI of the service, specifying the database name where we are going to get information: /denodo-odata.svc/<DBNAME>.
Below, there is an example where the accessible collections of movies database are actor, address, city, country, film and film_actor.
http://localhost:8080/denodo-odata.svc/movies
<?xml version='1.0' encoding='utf-8'?> <service xml:base="http://localhost:8080/denodo-odata.svc/movies/" xmlns="http://www.w3.org/2007/app" xmlns:atom="http://www.w3.org/2005/Atom"> <workspace> <atom:title>Default</atom:title> <collection href="actor"> <atom:title>actor</atom:title> </collection> <collection href="address"> <atom:title>address</atom:title> </collection> <collection href="city"> <atom:title>city</atom:title> </collection> <collection href="country"> <atom:title>country</atom:title> </collection> <collection href="film"> <atom:title>film</atom:title> </collection> <collection href="film_actor"> <atom:title>film_actor</atom:title> </collection> </workspace> </service> |
http://localhost:8080/denodo-odata.svc/movies/$metadata
Example of association that represents a relationship between country and city. Every country element is related with zero or more city elements:
<Association Name="country_city"> <Documentation> <Summary>Association between cities and countries</Summary> </Documentation> <End Type="com.denodo.odata2.country" Multiplicity="1" Role="country"/> <End Type="com.denodo.odata2.city" Multiplicity="*" Role="cities"/> <ReferentialConstraint> <Principal Role="country"> <PropertyRef Name="country.country_id"/> </Principal> <Dependent Role="cities"> <PropertyRef Name="city.country_id"/> </Dependent> </ReferentialConstraint> </Association> |
The Denodo OData Service maps these OData structures to VDP concepts like this:
Denodo ODATA Service |
VDP |
Entity Type |
View Definition |
Entity Type > Property |
View Column |
Entity Type > Navigation Property |
Association Role |
Association |
Association Definition |
Entity Set |
View Data |
Association Set |
(Associated data) |
Imported Functions |
- |
In the Service Metadata Document (see the Metadata section for more information) you can see the entity set names and to see its data you must use the following URL:
/denodo-odata.svc/<DBNAME>/collectionName
Example:
/denodo-odata.svc/movies/actor
Note that, for the sake of simplicity, we are removing the server and port from the examples.
Each item could be identified using its primary key property:
denodo-odata.svc/<DBNAME>/collectionName(keyvalue)
Examples:
/denodo-odata.svc/movies/actor(1)
/denodo-odata.svc/movies/store_category('F0')
The primary key can be a compound key, and in this case you must include all values separated by commas:
/denodo-odata.svc/<DBNAME>/collectionName(key1,key2)
Example:
/denodo-odata.svc/movies/film_actor(actor_id=1,film_id=1)
Properties of an entry can be accessed individually:
/denodo-odata.svc/<DBNAME>/collectionName(key)/propertyName
Example:
/denodo-odata.svc/movies/actor(1)/first_name
Response:
{ "d": { "first_name": "PENELOPE" } } |
The value of a property is available as a raw value:
/denodo-odata.svc/<DBNAME>/collectionName(key)/propertyName/$value
Example:
/denodo-odata.svc/movies/actor(1)/first_name/$value
Response:
PENELOPE |
Properties can be complex but they are also accessible. You must point out the property path, from the complex to the simple one:
/denodo-odata.svc/<DBNAME>/collectionName(pk)/propName/complexProp/propName
For example, for the following film_data complex field in a struct_table_film entity:
"table_id": "1", "film_data": { "__metadata": { "type": "com.denodo.odata2.struct_table_film_film_data" }, "id": "1", "title": "ACADEMY DINOSAUR", "description": "ELIZABETH" } |
we could perform the following call:
/denodo-odata.svc/movies/struct_table_film(1)/film_data/title
Response:
{ "d": { "title": "ACADEMY DINOSAUR" } } |
If you want to know the number of elements (entries) in a collection you have to add $count to the URL:
/denodo-odata.svc/<DBNAME>/collectionName/$count
Example:
/denodo-odata.svc/movies/actor/$count
Response:
200 |
OData resources can be represented in AtomPub (XML) or JSON, being AtomPub the default format.
Clients can request the format through the system query option $format or through the Accept header. In the case that both the Accept header and the $format query option are specified on a request, the $format query option has a higher precedence.
The example URLs below will show the same data but represented using the AtomPub format as defined in OData:Atom in the first one and in the second using the JSON format as defined in OData:JSON.
/denodo-odata.svc/movies/actor?$format=atom
/denodo-odata.svc/movies/actor?$format=json
Alternatively, this format can be requested using the HTTP header Accept:
Accept: application/json
Denodo Virtual DataPort allows you to define relationships between the elements of two views. The following example shows an association where the elements of the country view can be related with the elements of the city view. Every country is related with zero or more cities.
The association can be seen in the Service Metadata Document:
<Association Name="country_city"> <Documentation> <Summary></Summary> </Documentation> <End Type="com.denodo.odata2.country" Multiplicity="1" Role="country"/> <End Type="com.denodo.odata2.city" Multiplicity="*" Role="cities"/> <ReferentialConstraint> <Principal Role="country"> <PropertyRef Name="country.country_id"/> </Principal> <Dependent Role="cities"> <PropertyRef Name="city.country_id"/> </Dependent> </ReferentialConstraint> </Association> |
Denodo OData Service allows navigating the associations defined in VDP in order to get all the entities related with a particular entity. This is done by means of navigation properties.
/denodo-odata.svc/<DBNAME>/collectionName(key)/navigationPropertyName
For example, being cities a navigation property in the entity type country that navigates towards the city entity type:
/denodo-odata.svc/movies/country(1)/cities
Response:
{ "d": { "results": [ { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/movies/city(251)", "uri": "http://localhost:8080/denodo-odata.svc/movies/city(251)", "type": "com.denodo.odata2.city" }, "city_id": 251, "city": "Kabul", "country_id": 1, "last_update": "\\/Date(1139975125000+0060)\\/", "country": { "__deferred": { "uri": "http://localhost:8080/denodo-odata.svc/movies/city(251)/country" } } } ] } } |
You can get the links to the collection of entries relationed with one in particular:
/denodo-odata.svc/<DBNAME>/collectionName(key)/$links/navProp
The URL specified above will show all the URLs which allows the access to every entry associated with the entry collectionName(key) through the navigation property navProp.
Example:
/denodo-odata.svc/movies/country(2)/$links/cities
Response:
{ "d": [ { "uri": "http://localhost:8080/denodo-odata.svc/movies/city(59)" }, { "uri": "http://localhost:8080/denodo-odata.svc/movies/city(63)" }, { "uri": "http://localhost:8080/denodo-odata.svc/movies/city(483)" } ] } |
OData defines some query options that allows refining the requests: $filter, $select, $orderby and $expand.
A URI with a $filter system query option identifies a subset of the entries from the collection that satisfy the $filter predicate expression.
Expressions can reference properties and literals. The latter can be strings (enclosed in single quotes), the null literal, numbers or boolean values.
Denodo OData service supports the following operations and functions:
Operator |
Description |
Example |
eq |
Equal |
/actor?$filter=first_name eq 'GRACE' |
ne |
Not equal |
/actor?$filter=first_name ne 'GRACE' |
gt |
Greater than |
/actor?$filter=actor_id gt 5 |
ge |
Greater than or equal |
/actor?$filter=actor_id ge 5 |
lt |
Less than |
/actor?$filter=actor_id lt 10 |
le |
Less than or equal |
/actor?$filter=actor_id le 10 |
and |
Logical and |
/actor?$filter=actor_id gt 5 and actor_id lt 10 |
or |
Logical or |
/actor?$filter=actor_id lt 5 or first_name eq 'GRACE' |
not |
Logical negation |
/actor?$filter=not (actor_id eq 1) |
The following functions are available for strings operations:
The following table shows a summary and examples of this functions:
Function |
Example |
bool substringof(string p0, string p1) |
/actor?$filter=substringof('LO', first_name) eq true |
bool startswith(string p0, string p1) |
/actor?$filter=startswith(first_name, 'JO') eq true |
bool endswith(string p0, string p1) |
/actor?$filter=endswith(first_name,'ER') eq true |
int indexof(string p0, string p1) |
/actor?$filter=indexof(last_name, 'LO') eq 3 |
int length(string p0) |
/actor?$filter=length(first_name) eq 4 |
string substring(string p0, int pos) |
/actor?$filter=substring(first_name, 2) eq 'RO' |
string substring(string p0, int pos, int length) |
/actor?$filter=substring(first_name, 2,3) eq 'TTH' |
string tolower(string p0) |
/actor?$filter=tolower(first_name) eq 'nick' |
string toupper(string p0) |
/actor?$filter=toupper(first_name) eq 'NICK' |
string trim(string p0) |
/actor?$filter=trim(first_name) eq 'JENNIFER' |
string concat(string p0, string p1) |
/actor?$filter=concat( concat(first_name,', '), last_name) eq 'JENNIFER, DAVIS' |
There are three math functions: round, floor, ceiling. Each one allows Double or Decimal types as parameters and the returned value is of the same type as the parameter.
Function |
Example |
double round(double p0) |
/film?$filter=round(replacement_cost) eq 21 |
decimal round(decimal p0) |
/film?$filter=round(rental_rate) eq 1 |
double floor(double p0) |
/film?$filter=floor(replacement_cost) eq 20 |
decimal floor(decimal p0) |
/film?$filter=floor(rental_rate) eq 0 |
double ceiling(double p0) |
/film?$filter=ceiling(replacement_cost) eq 21 |
decimal ceiling(decimal p0) |
/film?$filter=ceiling(rental_rate) eq 1 |
Function |
Example |
int hour(DateTime p0) |
/actor?$filter=hour(last_update) eq 3 |
int minute(DateTime p0) |
/actor?$filter=minute(last_update) eq 34 |
int second(DateTime p0) |
/actor?$filter=second(last_update) eq 33 |
The $select system query option returns only the properties explicitly requested.
$select expression can be a comma-separated lists of properties or the star operator (*), which will retrieve all the properties.
Example:
/denodo-odata.svc/movies/actor?$select=actor_id,first_name,last_name
Response:
… { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/movies/actor(1)", "uri": "http://localhost:8080/denodo-odata.svc/movies/actor(1)", "type": "com.denodo.odata2.actor" }, "actor_id": 1, "first_name": "PENELOPE", "last_name": "GUINESS" }, … |
Another example:
/denodo-odata.svc/movies/actor?$select=*
Response:
… { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/movies/actor(1)", "uri": "http://localhost:8080/denodo-odata.svc/movies/actor(1)", "type": "com.denodo.odata2.actor" }, "actor_id": 1, "first_name": "PENELOPE", "last_name": "GUINESS", "last_update": "\\/Date(1139974473000+0060)\\/" }, … |
The $orderby query string option specifies the order in which items are returned:
/denodo-odata.svc/<DBNAME>/collectionName?$orderby=attribute [asc|desc]
To order the collection the resource path must identify a collection of entries, otherwise this option is unavailable.
The keywords asc and desc determine the direction of the sort (ascending or descending, respectively). If asc or desc are not specified items are returned in ascending order. Null values come before non-null values when sorting in ascending order and vice versa.
You can also sort by multiple attributes:
/denodo-odata.svc/<DBNAME>/collectionName?$orderby=attribute1[asc|desc],attribute2 [asc|desc]
Example:
/denodo-odata.svc/movies/address?$orderby=zip,client_identifier desc
$expand is available since Denodo Platform 6.0.
An $expand expression is a comma-separated list of navigation properties that specifies the related entities that should be represented inline.
Example:
/denodo-odata.svc/movies/country?$expand=cities
Response:
… "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/admin/country(1)", "uri": "http://localhost:8080/denodo-odata.svc/admin/country(1)", "type": "com.denodo.odata2.country" }, "country_id": 1, "country": "Afghanistan", "last_update": "/Date(1140007440000+0060)/", "cities": { "results": [ { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/admin/city(251)", "uri": "http://localhost:8080/denodo-odata.svc/admin/city(251)", "type": "com.denodo.odata2.city" }, "city_id": 251, "city": "Kabul", "country_id": 1, "last_update": "/Date(1140007525000+0060)/", "country": { "__deferred": { "uri": "http://localhost:8080/denodo-odata.svc/admin/city(251)/country" } } } ] } … |
The following is an example with two navigation properties. This URI identifies the film set as well as the film_actor (actors is the navigation property) and the film_category (categories is the navigation property) associated with each film:
/denodo-odata.svc/movies/film?$expand=film_actor,film_categories
Response:
... "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/admin/film(1)", "uri": "http://localhost:8080/denodo-odata.svc/admin/film(1)", "type": "com.denodo.odata2.film" }, "film_id": 1, "title": "ACADEMY DINOSAUR", "description": "A Epic Drama of a Feminist And a Mad Scientist who must Battle a Teacher in The Canadian Rockies", "release_year": "/Date(1136106000000+0060)/", "language_id": 1, "original_language_id": null, "rental_duration": 6, "rental_rate": "0.99", "length": 86, "replacement_cost": "20.99", "rating": "PG", "special_features": "Deleted Scenes,Behind the Scenes", "last_update": "/Date(1140008622000+0060)/", "film_actor": { "results": [ { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/admin/film_actor(actor_id 1,film_id=1)", "uri": "http://localhost:8080/denodo-odata.svc/admin/film_actor(actor_id 1,film_id=1)", "type": "com.denodo.odata2.film_actor" }, "actor_id": 1, "film_id": 1, "last_update": "/Date(1140008703000+0060)/", "actor_role": { "__deferred": { "uri": "http://localhost:8080/denodo-odata.svc/admin/film_actor(actor_id 1,film_id=1)/actor_role" } ...
"film_categories": { "results": [ { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/admin/film_category(film_ d=1,category_id=6)", "uri": "http://localhost:8080/denodo-odata.svc/admin/film_category(film_ d=1,category_id=6)", "type": "com.denodo.odata2.film_category" }, "film_id": 1, "category_id": 6, "last_update": "/Date(1140008829000+0060)/", "film": { "__deferred": { "uri": "http://localhost:8080/denodo-odata.svc/admin/film_category(film_ d=1,category_id=6)/film" } } } ] } ... |
Example with a multi-level relationship. This URI identifies the film set as well as each of the film_actor associated with each film. In addition, it also identifies the actors associated with each film_actor:
/denodo-odata.svc/movies/film?$expand=film_actor/actor
Response:
"__metadata": { "id": "http://localhost:8080/denodo-odata.svc/admin/film(1)", "uri": "http://localhost:8080/denodo-odata.svc/admin/film(1)", "type": "com.denodo.odata2.film" }, "film_id": 1, "title": "ACADEMY DINOSAUR", "description": "A Epic Drama of a Feminist And a Mad Scientist who must Battle a Teacher in The Canadian Rockies", "release_year": "/Date(1136073600000+0060)/", "language_id": 1, "original_language_id": null, "rental_duration": 6, "rental_rate": "0.99", "length": 86, "replacement_cost": "20.99", "rating": "PG", "special_features": "Deleted Scenes,Behind the Scenes", "last_update": "/Date(1140008622000+0060)/", "film_actor": { "results": [ { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/admin/film_actor(actor_id 1,film_id=1)", "uri": "http://localhost:8080/denodo-odata.svc/admin/film_actor(actor_id 1,film_id=1)", "type": "com.denodo.odata2.film_actor" }, "actor_id": 1, "film_id": 1, "last_update": "/Date(1140008703000+0060)/", "actor": { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/admin/actor(1)", "uri": "http://localhost:8080/denodo-odata.svc/admin/actor(1)", "type": "com.denodo.odata2.actor" }, "actor_id": 1, "first_name": "PENELOPE", "last_name": "GUINESS", "last_update": "/Date(1140006873000+0060)/", "film_actor": { "__deferred": { "uri": "http://localhost:8080/denodo-odata.svc/admin/actor(1)/film_actor" } } }, "film": { "__deferred": { "uri": "http://localhost:8080/denodo-odata.svc/admin/film_actor(actor_id 1,film_id=1)/film" } } }, … |
With the $top option you can select the n first entries of the collection, being n a non-negative integer:
/denodo-odata.svc/<DBNAME>/collectionName?$top=n
Note that n is a positive integer, a negative value means that the URL is malformed.
Example:
/denodo-odata.svc/movies/address?$top=1
Response:
{ "d": { "results": [ { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/movies/address('C001')", "uri": "http://localhost:8080/denodo-odata.svc/movies/address('C001')", "type": "com.denodo.odata2.address" }, "client_identifier": "C001", "street": "3989 Middlefield Rd", "city": "San Jose", "zip": "94085", "state": "CA", "primary_phone": "(408) 813-9318", "country": "UNITED STATES" } ] } } |
With the option $skip, the n first entries of the collection will not be shown in the response. n is a non-negative integer.
denodo-odata.svc/<DBNAME>/collectionName?$skip=n
Example:
/denodo-odata.svc/movies/address?$skip=79
Response:
{ "d": { "results": [ { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/movies/address('C080')", "uri": "http://localhost:8080/denodo-odata.svc/movies/address('C080')", "type": "com.denodo.odata2.address" }, "client_identifier": "C080", "street": "2347 Santa Ana St", "city": "Palo Alto", "zip": "94303-3141", "state": "CA", "primary_phone": "(650) 856-9738", "country": "UNITED STATES" } ] } } |
The number of entries in a collection identified by the resource path section of the URI may be added to the data shown in the response using the $inlinecount system query option. This option allow two possible values:
Note that the count is calculated after applying any $filter system query options present in the URI.
Examples:
/denodo-odata.svc/movies/actor?$inlinecount=allpages
Response:
{ "d": { "__count": "200", "results": [ … ] } } |
Another example:
/denodo-odata.svc/movies/actor?$inlinecount=allpages&$filter=actor_id eq 1
Response:
{ "d": { "__count": "1", "results": [ { "__metadata": { "id": "http://localhost:8080/denodo-odata.svc/movies/actor(1)", "uri": "http://localhost:8080/denodo-odata.svc/movies/actor(1)", "type": "com.denodo.odata2.actor" }, "actor_id": 1, "first_name": "PENELOPE", "last_name": "GUINESS", "last_update": "\\/Date(1139974473000+0060)\\/" } ] } } |
Another example:
/denodo-odata.svc/movies/actor?$inlinecount=none
Response:
Actor data, just like without $inlinecount option.
Whenever the Denodo OData Service has to return a collection of entries which size exceeds that configured at the server.pageSize property of its configuration file, it will split the response into pages, returning only the first 1000 entries (the default value for page size).
Denodo OData Service will add to the response a next link, which will easily allow the client to request the next page of results.
Next links include a $skiptoken parameter. They look like this:
/denodo-odata.svc/movies/actor?$skiptoken=1
If the original request includes query options, the result will show the next link with these query options and a $skiptoken as in the examples below.
Example request:
/denodo-odata.svc/movies/actor?$top=2
Response:
... "__next": "http://localhost:8080/denodo-odata.svc/movies/actor?$top=2&$skiptoken=1" ... |
For debug purposes there is a possibility to enrich the OData service response with additional helpful data.
The additional data consists of information about the request, the response, the parsed request URI, the server environment, library timings, and the stack trace in case an error occurred.
To request the debug output for a request to the OData service the query parameter odata-debug=json or odata-debug=html must be appended to the original request URL:
http://localhost:8080/denodo-odata.svc/movies/?odata-debug=json
The access to Denodo databases via this Denodo OData Service is read-only.
OData 2.0 does not support Collections/Bags/Lists that will allow us to give support to arrays as complex objects. Now they are displayed between square brackets as a comma-separated list of values.
Denodo OData Service does not support arithmetic operators: add (addition), sub (subtraction), mul (multiplication), div (division) and mod (modulo).
Denodo OData Service does not provide support for the string function replace:
Denodo OData Service does not provide support for date functions:
Denodo OData Service does not provide support for type functions:
Denodo OData Service does not allow navigation properties as selection clauses.
When there is an association where one of the elements of an end point is a field of a register, Denodo Virtual DataPort does not allow the navigation from the endpoint with the complex property.
Denodo Virtual DataPort does not support the order by clause using fields of registers, therefore the $orderby query string option is not available if you want to sort by a field of a complex property
This system query option indicates that entries associated with the elements identified by the resource path section must be represented inline.
Navigational queries does not allow the count(*) function, then if the URL contains a navigation the option of counting entries in a collection ($count) is not available.