Flat view

Usage

Rationale

If you're using Oracle, SQL Server [SINCE Orbeon Forms 2016.2], DB2 [SINCE Orbeon Forms 4.7], PostgreSQL [SINCE Orbeon Forms 4.8], or MySQL [SINCE Orbeon Forms 2024.1], when you deploy a form created in Form Builder, Orbeon Forms can create a form-specific view of your data, with one column for each form field.

Property to enable

You enable this feature by setting the relevant property listed below to true.

Database	Property
Oracle	oxf.fr.persistence.oracle.create-flat-view
MySQL	oxf.fr.persistence.mysql.create-flat-view
SQL Server	oxf.fr.persistence.sqlserver.create-flat-view
PostgreSQL	oxf.fr.persistence.postgresql.create-flat-view
DB2	oxf.fr.persistence.db2.create-flat-view

For instance, if using Oracle, you set:

<property
    as="xs:boolean"
    name="oxf.fr.persistence.oracle.create-flat-view"
    value="true"/>

Generated names

View name

When you enable this property, upon publishing a form, the persistence layer creates a view specific to that form. The name of the view is based on the app name, form name, and [SINCE Orbeon Forms 2021.1] form version. It has the form:

[SINCE Orbeon Forms 2021.1] orbeon_f_#{app}_#{form}_#{form_version}
[UP TO Orbeon Forms 2020.1] orbeon_f_#{app}_#{form}

For instance, on Orbeon Forms 2021.1 and newer, if your app is hr, your form is expense, and you are publishing version 2 of that form, then the view is named orbeon_f_hr_expense_2. If upon publishing, there is already a view with that name, the persistence layer deletes it before recreating a new view.

[SINCE Orbeon Forms 2024.1] One extra view will be created for each repeated section and grid, if any. In that case, the view name will be suffixed with the name of the repeated section or grid.

orbeon_f_#{app}_#{form}_#{form_version}_#{repeated_section_or_grid}

Metadata column names

Each view always has one or more metadata columns, with information copied from the equivalent columns in orbeon_form_data. For views related to repeated sections or grids, only the metadata_document_id column is included.

• [UP TO Orbeon Forms 4.3]

  • metadata_document_id

  • metadata_created

  • metadata_last_modified

  • metadata_username

• [SINCE Orbeon Forms 4.4]

  • metadata_document_id

  • metadata_created

  • metadata_last_modified_time

  • metadata_last_modified_by

Note that there is no metadata_draft column, as drafts are not included the view. (Before 4.7 they were, incorrectly, see issue 1870.)

Repetition column names

[SINCE Orbeon Forms 2024.1] For repeated sections and grids, the view includes the repetition number for the current repeated section or grid, as well as for any enclosing repeated section. The column names are generated as follows:

#{repeated_section_or_grid}_repetition

Data column names

In addition to the metadata and repetition columns, one column is created for each form field. Each column is named using the control name, optionally prefixed with enclosing section/grid names. See below for details on how column names are generated depending on the version of Orbeon Forms you are using.

As databases limit the length of column names, the persistence layer truncates them if needed. It also converts dashes to underscores, and removes any non-alphanumeric character except inner underscores.

With Orbeon Forms 2024.1 and newer

By default, the column names are generated using the control names only, unless they are located in a section template, in which case they will be prefixed with the name of the template section.

To get the previous behavior (Orbeon Forms 2023.1 and earlier), where the names of all enclosing sections/grids are included in the column names, the following property can be changed from false to true:

<property
  as="xs:boolean"
  name="oxf.fr.persistence.[provider].flat-view.prefixes-in-main-view-column-names"
  value="false"/>

This property doesn't affect column names in views for repeated sections and grids. In those views, the names of enclosing sections/grids are never included in the column names.

In previous versions, column names were always truncated to 30 characters. With Orbeon Forms 2024.1 and newer, they are now truncated to a number of characters which depends on the database used. Those limits are defined in properties, which can be overridden if needed:

<property
  as="xs:integer"
  name="oxf.fr.persistence.oracle.flat-view.max-identifier-length"
  value="128"/>
<property
  as="xs:integer"
  name="oxf.fr.persistence.mysql.flat-view.max-identifier-length"
  value="64"/>
<property
  as="xs:integer"
  name="oxf.fr.persistence.postgresql.flat-view.max-identifier-length"
  value="63"/>
<property
  as="xs:integer"
  name="oxf.fr.persistence.db2.flat-view.max-identifier-length"
  value="128"/>
<property
  as="xs:integer"
  name="oxf.fr.persistence.sqlserver.flat-view.max-identifier-length"
  value="128"/>

With Orbeon Forms 4.5 and newer

Orbeon Forms 4.5 introduces a new truncation algorithm so names are not cut short unnecessarily, and a numerical suffix is used instead for those columns which would introduce duplicates.

Examples:

• Section name: personal-information

  • Control name: first-name ⇒ column name: personal_informatio_first_name

  • Control name: last-name ⇒ column name: personal_information_last_name

  • Control name: address ⇒ column name: personal_information_address

• Section name: company

  • Control name: name ⇒ column name: company_name

  • Control name: industry ⇒ column name: company_industry

• Section name: section-with-long-name

  • Control name: my-control-with-a-pretty-long-name ⇒ column name: section_with_l_my_control_with

  • Control name: my-control-with-a-pretty-long-name-too ⇒ column name: section_with_l_my_control_wit1

  • Control name: my-control-with-a-pretty-long-name-really ⇒ column name: section_with_l_my_control_wit2

Enclosing section and grid names are always included in the column names. A truncation limit of 30 characters is enforced.

With Orbeon Forms 4.4 and earlier

The section name is truncated to 14 characters, the control name to 15 characters, and both are combined with an underscore in between. In the vast majority of the cases, this will result in distinct and recognizable column names. In cases where two or more columns would end up having the same name or conflict with one of the metadata column, the persistence layer adds a number prefix of the form 001_, 002_, 003_… to each column to make it unique. If this happens, you might want to change your section and/or control names to have more recognizable column names.

Examples:

Section name	Control name	Column name
personal-information	first-name	PERSONAL_INFOR_FIRST_NAME
last-name	PERSONAL_INFOR_LAST_NAME
address	PERSONAL_INFOR_ADDRESS
company	name	COMPANY_NAME
industry	COMPANY_INDUSTRY

Limitations

• The Multiple File Attachments control is not supported, see issue 6296.

• Only the default form data format is supported, see issue 4440.

• With MySQL, fields within repeated sections or grids are not supported. This is because the MySQL built-in XML function ExtractValue() is quite limited and does not directly support returning multiple rows from a single XML document.

• Flat views are not supported at all with SQLite.

• [SINCE Orbeon Forms 2016.1] Fields inside nested sections and nested section templates are supported.

• [SINCE Orbeon Forms 2024.1] Fields inside repeated sections or grids are also supported.