Emojis SQL in ICM InfoWorks - 11 One-To-Many Links 🌐

 11 One-To-Many Links 🌐

One-to-many links enable queries to consider linked objects, even when there's a possibility of having none, one, or multiple linked objects.

The keywords all_us_links and all_ds_links help in joining ALL upstream or downstream links to any node or link type.

Available One-To-Many Links:

From	To	Name
Node	Link	us_links
Node	Link	ds_links
Node	Subcatchment	subcatchments
Link	Link	us_links
Link	Link	ds_links
Subcatchment	Lateral link	drains_from
Subcatchment	Lateral link	lateral_connected_links

🔍 How to Use them in Queries:

11.1 Determining Linked Objects 🔗

Utilize ANY(linkname.*) to check if linked objects exist. Example: ANY(us_links.*)

11.2 Counting Linked Objects 🧮

Employ COUNT(linkname.*) to tally the linked objects. For instance: COUNT(manhole_surveys.*)=0

11.3 Aggregate Functions 📊

Almost all aggregate functions from the array fields section, except FIRST and LAST, apply for one-to-many links.

11.4 'Bare' One-To-Many Fields Usage 📋

You can assign values to one-to-many fields through an assignment clause outside an aggregate function. For example:

• With only a SET sub-clause: SET us_pipes.width = 123 sets the width for every upstream pipe.
• With a WHERE sub-clause: SET us_links.width = 234 WHERE shaft_depth = 1650 will adjust the width for every upstream link where the shaft depth equals 1650.

11.5 Interplay Between 'Bare' Fields & Aggregate Functions ⚙️

If one-to-many field values are used outside aggregate functions in a WHERE sub-clause and inside aggregate functions in the SET sub-clause, the aggregate functions in the SET sub-clause will only be evaluated for objects linked to the current object where the WHERE sub-clause holds true.

However, if you incorporate an aggregate function IN the WHERE sub-clause, it will run for all objects linked via the one-to-many link to the current object.