XML Elements in T3DataStructure

This is the list of elements and their nesting in the Data Structure.

Elements Nesting Other Elements ("Array" Elements)

All elements defined here cannot contain a string value but must contain a set of elements.

(In a PHP array this corresponds to saying that all these elements must be arrays.)

Changed in version 12.0

The superfluous array key TCEforms was removed and is not evaluated anymore. Its sole purpose was to wrap real TCA definitions. The TCEforms tags should be removed upon dropping TYPO3 v11 support. In TYPO3 v12 there is an automatic migration that will be removed in a future version.

<T3DataStructure>

Type: array

This is the root element of a T3DataStructure. It may contain tags <meta> and <ROOT> or <sheets>

<T3DataStructure>

Type: array

Can contain application specific meta settings. Interpretation depends on the application using the T3DataStructure. Each setting goes to a XML tag.

<ROOT>

Type: array

Defines an "object" in the Data Structure

Tag <ROOT> is reserved for the first element in the Data Structure. The <ROOT> tag must have a <type> tag with the value "array" as child and then define other objects nested in <el> tags.

Can have the following child tags: <type>, <section>, <el> <[application tag]>.

<[field name]>

Type: array

Defines an "object" in the Data Structure, [field name] defines the objects name.

Can have the same child tags like <ROOT>.

<sheets>

Type: array

Defines a collection of "sheets" which is like a one-dimensional list of independent Data Structures.

Contains <[sheet name]> tags for the actual sheets.

<sheetTitle>

Type: string or LLL reference

Title of the sheet. Mandatory for any sheet except the first (which gets "General" in this case). Can be a plain string or a reference to a language file using standard LLL syntax. Ignored if sheets are not defined for the FlexForm.

<displayCond>

Type: array

Condition that must be met in order for the sheet to be displayed. If the condition is not met, the sheet is hidden.

For more details refer to the description of the "displayCond" property in the TCA Reference.

<[sheet ident]>

Type: array

Defines an independent data structure starting with a <ROOT> tag.

Alternatively, it can be a plain value referring to another XML file which contains the <ROOT> structure. See example later.

<el>

Type: array

Contains a collection of Data Structure "objects"

Elements can use the attribute type to define their type, for example they can explicitly use boolean.

An example would look like:

<required type="boolean">1</required>

Elements Containing Values ("Value" Elements)

All elements defined here must contain a string value and no other XML tags whatsoever!

(In a PHP array this corresponds to saying that all these elements must be strings or integers.)

<type>

Type: Keyword string: "array", "" (blank)
Default: "" (blank)

Defines the type of object.

"array": The parent tag contains a collection of other objects defined inside the <el> tag on the same level. If the value is "array" you can use the tag <section>. See below.
"" (blank): The parent does not contain sub objects. The meaning of an object is determined by the application using the data structure. For FlexForms this object would draw a form element.

If the parent is <ROOT> this tag must have the value "array".

<section>

Type: Boolean
Default: "" (blank)

Defines that an object of type <array> must contain other "array" objects in each item of <el>. The meaning of this is application specific. For FlexForms it will allow the user to select between possible arrays of objects that they can create in the form. This is similar to the concept of IRRE / inline TCA definitions.

Changed in version 13.0

Available element types inside FlexForm sections is restricted. You should only use simple TCA types like type => 'input' in sections. Relations (type => 'group', type => 'inline', type => 'select' and similar) should be avoided. TYPO3 v13 forbids using type => 'select' with a foreign_table set, which will raise an exception. This does not apply for FlexForm fields outside of a <section>. Details can be found in Breaking: #102970 - No database relations in FlexForm container sections.

T3DataStructure example: A simple FlexForm

Below is the structure of a basic FlexForm from the example extension typo3/cms-styleguide :

EXT:styleguide/Configuration/FlexForms/Simple.xml

<T3DataStructure>
    <sheets>
        <sDEF>
            <ROOT>
                <sheetTitle>Sheet Title</sheetTitle>
                <type>array</type>
                <el>
                    <input_1>
                        <label>input_1</label>
                        <config>
                            <type>input</type>
                        </config>
                    </input_1>
                </el>
            </ROOT>
        </sDEF>
    </sheets>
</T3DataStructure>

For a more detailed example, have a look at the plugin configuration of system extension felogin (EXT:felogin/Configuration/FlexForms/Login.xml (GitHub)). It shows an example of a relatively complex data structure used in a FlexForm.

More information about using FlexForms can be found in the relevant section of the TCA reference.