This is one of the tracker field types in Trackers. See also Relations Tracker Field

The item link field provides a selection list with all the unique values in a particular field of another tracker. This allows the use of trackers for simple relational database applications. Using an items list field instead of a text field or text area guarantees that always the same text/phrase is used to describe something, which helps in searching etc.
Especially powerful is the combination with the filter field and filter value options of the TrackerList plugin, which allows the display of only those tracker fields on a particular topic. To use this, the same exact phrase in every record of the tracker is required, which the items list field makes possible.

You want to display the list of products of a company

• tracker Company (id 6)
  • id 14: Company name - text field
  • id 16: Product list - items list = 5,15,leave localFieldId blank since remote field is a itemlink back to this tracker,12
  • id 17: Address - text field

Note: prior to Tiki 9, you have to specify the localFieldId even of the remote field is an itemLink field. From Tiki 9, the localFieldId is used only when you are trying to match values and not simply looking for items that are linked back here.

• tracker Products (id 5)
  • id 12: Product name - text field
  • id 15: Company name - item link 6,14

The view of the tracker Company will look like

The view of the tracker Products will look like

The insert of a Product item will look like

Company name will be drop down with Macromedia, Apple, Microsoft

In the above example, Company name in Products tracker is a item link
If you add the option 1 to the item link parameter, you will create a link to the company when displaying a product
If you use the parameters 6,14,0,14|17, instead of seeing the company name, you will see the company name concatenated to the address.

PS: If the Company tracker is not know before you enter the products, you will have not to use the itemlink type for the field 15 but a simple text field.
PPS: Since Tiki8, the new interface to edit tracker fields and their options does not allow to modify the type of a field once it is created.

Do not forget the result can be a list

FieldIdThere can be a list of fieldId - so that you cross as many trackers you want. For instance imagine your product tracker has a field contact(fieldId=50) that is an item link to a person tracker , and imagine the person tracker has 2 fields : a name (fieldId=51) and a phone number (fieldId:52)
If you want to display the phone numbers of all your product contact in the company tracker, you will have a field 5,15:50:51,14,52
To visualize you can use this kind of table

Since Tiki8, there is a new interface to edit tracker fields and their options, and thus, this tracker field looks like:

In the case below, both 29 and 30 are "text" fields.

In Tiki9 some new options were added to "item link", which include:

• allow selecting more than one item from Tracker B as linked with that item in Tracker A,
• you can use a "static text" tracker item field as a separator for the fields displayed from each item in tracker B (for instance, a " dash " ( - ) can be used )
• and many other improvements (see some in the image below).

New options have been added in Tiki17 to the tracker field "item link", which allow to display the linked items as a table with the UI and potential features of PluginTrackerList, which opens the door to have custom inline editable fields, sortable tables, etc.

In addition, you can get sums of values of the linked tracker items in a mathematical calculation field in the same source tracker. See an example in the profile Work_Custom_Pricing

When editing that field, you can select through checkboxes which items you want to be really linked (from all the ones matching the pre-selection method defined in the tracker field definition.

Those ones selected (two out of three in the previous screenshot) are the ones taken into account later on as linked and shown in the table display, and used in the mathematical calculation formula in the corresponding tracker fields of that profile.

As previously indicated, you can indicate which fields you want displayed, which format, the options you want to be used in the table display, the pre-selection match criteria, and a few other options:

As indicated above, see more details in your own tiki instance after applying profile Work_Custom_Pricing

Since Tiki17 (backported to Tiki 16.2 ), you can use wildcard items in the remote tracker:

1. the tracker field can display items from the remote tracker which match the value of the common field between the two tracker plus those with a wildcard (asterisk, *) in that field.
   • An Update button is shown then below the table, which will proceed as follows:
     • all selected wildcard items are cloned and become linked items
     • all selected normal items stay the same
     • all unselected normal items are deleted
     
     This allows users to make some selections, update, then edit as necessary. Cloned items are safe to edit (they no longer edit the wildcard item but the cloned one), and then save the whole form.
     The Update button makes sure this works for new items when we still don't have the itemId to clone to, etc.

ItemsList field can now use an already present DynamicItemList link to another tracker to list fields in addition to ones displayed in DynamicItemsList. For this purpose, Link Field ID must be left empty and Value Field ID must be set to the DynamicItemList field.

ItemsList fields Editable: In edit and view mode, ItemsList fields now offer these options: add item, edit item, delete item.
(See: https://dev.tiki.org/item7206-Make-ItemsList-Tracker-Fields-Editable)

See also Dynamic items list.

Items list | item link | item list | items link | tracker field items list | tracker field item link | tracker field item list | tracker field items link | itemslist | itemlink | itemlist | itemslink | foreign key | Wildcard items | Wildcard | Wildcard_items | WildcardItems