Queries (`OrchardCore.Queries`)¶

The queries module provides a management UI and APIs for querying data.

Creating custom query sources¶

Query¶

Create a class inheriting from Query which will represent the state that is necessary to represent this new query.

QuerySource¶

Create a class implementing IQuerySource in order to expose the new type of query.
The query source can be registered like this:

services.AddScoped<IQuerySource, LuceneQuerySource>();

Editors¶

Queries are edited by providing a custom implementation of a DisplayDriver for the type Query.

public class LuceneQueryDisplayDriver : DisplayDriver<Query, LuceneQuery>
{
...
}

Queries dialog¶

When the list of query types is displayed, a template for the shape Query_Link__[QuerySource] will be used.
For instance, if the source is Lucene then the file Query-Lucene.Link.cshtml will be used.

Recipe step¶

Queries can be created during recipes using the queries step.
Here is a sample step:

{
    "name": "queries",
    "Queries": [ {
        // Common properties
        "Name": "AwesomeQuery",
        "Source": "Lucene",
        // Properties of the concrete query
        ...
        }
    ]
}

Web APIs¶

`api/queries/{name}`¶

Executes a query with the specified name.

Verbs: POST and GET

Parameter	Example	Description
`name`	`myQuery`	The name of the query to execute.
`parameters`	`{ size: 3}`	A Json object representing the parameters of the query.

GraphQL¶

When exposing queries (Lucene or SQL) through GraphQL, you need to define schema of a query return type.
There are two options: To return a ContentItem or to return a custom object.

If you want to expose ContentItems (e.g. of type BlogPost), you need to check Return Content Items checkbox and define Schema like this:

{
    "type": "ContentItem/BlogPost"
}

However, if you want to expose a custom object (e.g. only DisplayText), you need to uncheck Return Content Items checkbox and change Schema to look like this:

{
    "type": "object",
    "properties": {  
        "Content.ContentItem.DisplayText" : {
            "type" : "string",
            "description" : "This is BlogPost display text."
        }
    }
}

Where properties can either be of string or integer type.

For Lucene queries with custom object schema, you are limited to elements stored in Lucene index.

For SQL queries, you can expose any column where property name is a column alias from the query.

Note

When returning documents from a SQL query, make sure your query returns a list of document IDs. This is commonly available in the DocumentId column, but check the tables you're querying.

Here is an example of a custom Query from a manually added table in a database :

-- On the Query don't check the "return content items" checkbox
SELECT Name FROM Test

Here is how you would define a Schema for this Query to add it to the GraphQL endpoint.

{
    "type": "object",
    "properties": {  
        "Name" : {
            "type" : "string",
            "description" : "This is your custom table 'Name' column."
        }
    }
}

If your Query has the same name as a content type name it could lead into having them colliding in the GraphQL endpoint. For SQL and Lucene queries you can then define a custom field type name in their schema.

{
    "type": "object",
    "fieldTypeName": "customGraphQLFieldTypeName",
    "properties": {  
        "Name" : {
            "type" : "string",
            "description" : "This is your custom table 'Name' column."
        }
    }
}

SQL Queries (`OrchardCore.Queries.Sql`)¶

This feature provides a new type of query targeting the SQL database.

Queries recipe step¶

Here is an example for creating a SQL query from a Queries recipe step:

{
    "Source": "Sql",
    "Name": "ContentItems",
    "Template": "select * from ContentItemIndex", // json encoded query template
    "ReturnContentItems": false
}

Liquid templates¶

You can access queries from liquid views and templates by using the Queries property.
Queries are accessed by name, for example Queries.RecentBlogPosts.

query¶

The query filter provides a way to execute queries.

{% assign recentBlogPosts = Queries.RecentBlogPosts | query %}
{% for item in recentBlogPosts %}
{{ item | display_text }}
{% endfor %}

The example above will iterate over all the results of the query name RecentBlogPosts and display the text representing the content item.
Any available property on the results of the queries can be used. This example assumes the results will be content items.

Parameters¶

The query filter allows you to pass in parameters to your parameterized queries. For example, a query called ContentItems that has two parameters (contentType and limit) can be called like this:

{% assign fiveBlogPosts = Queries.ContentItems | query: contentType: "BlogPost", limit: 5 %}

Razor Helpers¶

The QueryAsync and ContentQueryAsync Orchard Helper extension methods (in the OrchardCore.Queries and OrchardCore.ContentManagement namespaces respectively) allow you to run queries directly from razor pages.

You can use the DisplayAsync extension method (also in OrchardCore.ContentManagement) to display the content items returned from ContentQueryAsync.

For example, to run a query called RecentBlogPosts, and display the results:

@foreach (var contentItem in await Orchard.ContentQueryAsync("RecentBlogPosts"))
{
    @await Orchard.DisplayAsync(contentItem)
}

The Razor Helper is accessible on the Orchard property if the view is using Orchard Core's Razor base class, or by injecting OrchardCore.IOrchardHelper in all other cases.

Executing SQL Queries¶

RDBMS support¶

Because RDBMS vendors support different SQL flavors this module will analyze the query you defined and render a specific one based on the RDBMS that is used.
This also allows the queries to be exported and shared across website instances even if they run on different RDBMS.

Examples¶

Here is an example of a query that returns all published Blog Posts:

    select DocumentId
    from ContentItemIndex 
    where Published = true and ContentType = 'BlogPost'

By selecting the "Return documents" options, the content items associated with the resulting DocumentId values are loaded.

The example below returns a custom set of values instead of content items:

select
    month(CreatedUtc) as [Month],
    year(CreatedUtc) as [Year],
    day(CreatedUtc) as [Day],
    count(*) as [Count]
from ContentItemIndex 
where Published = true and ContentType = 'BlogPost' and PublishedUtc > now()
group by day(CreatedUtc), month(CreatedUtc), year(CreatedUtc)

SQL Parameters¶

Parameters can be provided when running queries.
Parameters are safe to use as they will always be parsed before being included in a query.
The syntax of a parameter is @name:default_value, where name is the name of the parameter, and default_value an expression (usually a literal) to use in case the parameter is not defined.

The following example loads the document ids for a parameterized content type:

select DocumentId
from ContentItemIndex 
where Published = true and ContentType = @contenttype:'BlogPost'

If the contenttype parameter is not passed when the query is invoked, then the default value is used.

Parameter names are case-sensitive.

Templates¶

A SQL query is actually a Liquid template. This allows your queries to be shaped based on the parameters it gets.
When injecting user-provided values, be sure to encode these such that they can't be exploited.
It is recommended to use parameters to inject values in the queries, and only use Liquid templates to change the shape of the query.

This example checks that a limit parameter is provided and if so uses it:

{% if limit > 0 %}
    select ... limit @limit
{% else %}
    select ...
{% endif %}

Paging¶

Use LIMIT [number] and OFFSET [number] to define paged results.

These statements will be converted automatically based on the RDBMS in use.

Helper functions¶

The SQL parser is also able to convert some specific functions to the intended dialect.

Name	Description
`second(_date_)`	Returns the seconds part of a date.
`minute(_date_)`	Returns the minutes part of a date.
`hour(_date_)`	Returns the hours part of a date.
`day(_date_)`	Returns the days part of a date.
`month(_date_)`	Returns the months part of a date.
`year(_date_)`	Returns the years part of a date.
`now()`	Returns current date time (utc).

Scripting¶

The following JavaScript functions are available with this module.

Function	Description	Signature
`executeQuery`	Returns the result of the query.	`executeQuery(name: String, parameters: Dictionary<string,object>): IEnumerable<object>`

Videos¶

Breaking changes¶

1.0 -> 1.1

The Query API now returns an IQueryResults which now will also contain a count for the Lucene results. The JSON data structure has changed from :

[
    {...}
]

To :

{
  items:[...],
  count:1231
}

Queries (OrchardCore.Queries)¶