Data Retrieval

Retrieving data

Fetching all users

The FETCH should be read as: fetch all user entities and rename the name property to "Name".

SQL

FETCH user (key, name AS "Name")

Will yield the result, notice the column names:

key	Name
1	user1
2	user2

Fetching users filtered by name

The FILTER directive at line 2 should read as: filter user entities by their name property and match only those that end in 1.

SQL

FETCH user (key, name)
FILTER AND (name LIKE "%1")

Will yield the results:

key	Name
1	user1

Fetching all users and their type

SQL

FETCH user (key, name AS "Name") {
    user_type TO id_user (type AS "Type")
}

Will yield the result, notice the column names:

key	Name	Type
1	user1	Admin
2	user2	User

Fetching users by filtered by type

SQL

FETCH user (key, name) {
    user_type TO id_user (type)
        FILTER AND (type == "Admin")
}

Will yield the results:

key	name	type
1	user1	Admin

Overview

FETCH is a custom query language that allows retrieving, filtering and aggregating data from one or more entities. It is used throughout the entire system to define search views, catalogs, charts, reports and much more.

Filtering

Filtering helps retrieve only the required data. Let's say we have an entity car with a property year_of_manufacturing and we want all the cars newer than 2015.