TranslateProject/sources/tech/20191001 How to create the data structure for a Corteza Low Code application.md

[#]: collector: (lujun9972)
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[#]: subject: (How to create the data structure for a Corteza Low Code application)
[#]: via: (https://opensource.com/article/19/10/corteza-low-code-data-structure)
[#]: author: (Lenny Horstink https://opensource.com/users/lenny-horstink)

How to create the data structure for a Corteza Low Code application
======
Corteza is an open source alternative to Salesforce. Learn how to use it
in this series.
![Green graph of measurements][1]

In the [first article][2] in this series, I showed how to create a custom application to track donations using Corteza Low-Code, a graphical user interface- (GUI) and web-based development environment that serves as an alternative to Salesforce. So far, the Donations application merely exists, but this article explains how to make it do something by populating it with a data structure using modules and fields.

Modules and fields exist inside your application. (In programming terminology, they are "locally defined.") Modules and fields define places where data is stored in your application. Without modules and fields, your application has no memory nor anything to work with, so defining them is the next step when creating a new app.

The [Donations application][3] is available on the Corteza community server. You need to be logged in or create a free Corteza community server account to check it out.

### Enter the application's admin area

To enter the admin area of an application, you first need to open the application inside Corteza Low-Code. To enter the Donations application created in the first part of this series:

  1. Enter Corteza. (Read [_Intro to Corteza, an open source alternative to Salesforce_][4] if you need some background on this.)
  2. Click on the **+** button to create a new tab.
  3. Select Corteza Low-Code.
  4. Click on the Donations namespace to enter the Donations application.



Since the Donations application doesn't have any modules or pages yet, the only thing you see is an **Admin panel** link on the right. If the applications had pages, it would show the main menu and the **Admin panel** link on the far right.

![Open Corteza Low Code admin panel][5]

Click on it to enter the application's admin area. There are four menu items:

![Corteza Low Code admin panel menu][6]

  * **Modules:** Create or edit modules and fields
  * **Pages:** Define the visual part of your application
  * **Charts:** Create charts to add to pages
  * **Automation:** Add automation rules to automate business processes and workflows



The **Public pages** link takes you back to your application.

### Create modules and fields

Modules and fields define what data you need to store in your application and how that data links to other data. If you've ever built a database with [LibreOffice Base][7], Filemaker Pro, or a similar application, this might feel familiar—but you don't need any database experience to work with Corteza.

#### Modules

A module is like a table in a database. A simple application typically has a few modules, while bigger applications have many more. Corteza CRM, for example, has over 35. The number of modules an application can have is unlimited.

A new application does not have any modules. You can create one by using the form on top or by importing an existing module from a different application using an export file. You can import and export individual modules or all modules at the same time.

When you create a module, best practice is to give it a descriptive name without spaces and using capital letters on different words, e.g., _Lead_, _Account_, or _CaseUpdate_.

The Donations application includes the following modules:

  * **Contact:** To store the donor's contact data
  * **ContactDonation:** To track a contact's donation(s)
  * **Project:** To store a project you can assign donations to
  * **Note:** To store notes related to a project



![Donations application modules][8]

#### Fields

Each module consists of a set of fields that define what data you want to store and in what format.

You can add new fields to a module by using the **Add new field** button. This adds a new row with the following fields:

  * **Name:** It must be unique and cannot have spaces, e.g., "firstname." This is not shown to the end user.
  * **Title:** This is the field's label—the field name the end users see when they view or edit a record. It can contain any character, including spaces. Although it's best practice to keep this title unique, it's not mandatory. An example is "First name."
  * **Type:** This is where you set the field type. The wrench icon on the right allows you to set more detailed data for the field type.
  * **Multiple values:** This checkbox is available when you want a field type to allow multiple value entries.
  * **Required:** This makes the field mandatory for the end user when creating or editing a record.
  * **Sensitive:** This allows you to mark data that is sensitive, such as name, email, or telephone number, so your application is compliant with privacy regulations such as the [GDPR][9].



At the end of the row, you can find a **Delete** button (to remove a field) and a **Permission** button (to set read permissions and update field permissions per role).

### Field types

You can select from the following field types. The wrench icon beside the field type provides further options for each case.

  * **Checkbox (Y/N):** This field shows a checkbox to the end user when editing a record. When you click on the wrench icon, you can select what checked and unchecked represent. For example: Yes/No, Active/Inactive, etc.
  * **DateTime:** This makes a date field. You can select:
    * Date only
    * Time only
    * Past values only
    * Future value only
    * Output relative value (e.g., three days ago)
    * Custom output format (see [Moment.js][10] for formatting options)
  * **Email:** This field auto-validates whether the input is an email and turns it into a clickable email link in record-viewing mode. You can select the **Don't turn email into a link** option to remove the auto-link feature.
  * **Select:** When you click on the wrench icon, you can use the **Add** button to add as many Select options as you need. You can also set whether the end user can select multiple values at once.
  * **Number:** This field gives you the option to add a prefix (for example a $ for values in dollars), a suffix (for example % for a number that represents a percentage), and the decimal precision (e.g., zero for whole numbers or two for values like 1.13, 2.44, 3.98), and you can use the **Format Input** field to create more complex formats.
  * **Record:** This field allows you to link the current module to another module. It will show as a Select to the end user. You can select the module in the **Module name** field and choose the field to use to load the Select options. In **Query fields on search**, you can define what fields you want the user to be able to search on. As with the **Select** field type, you can set whether the user can select multiple values at once.
  * **String:** By default, a String field is a single-line text-input field, but you can choose to make it multi-line or even a rich text editor.
  * **URL:** The URL field automatically validates whether the field is a link to a site. You can select the following options for this field:
    * Trim # from the URL
    * Trim ? from the URL
    * Only allow SSL (HTTPS) URLs
    * Don't turn URL into a link
  * **User:** This creates a Select field that loads with all users in Corteza. You can preset the value to the current user.
  * **File:** This creates a **File Upload** button for the end user.



#### Field types in the Donations application

The Donations application includes the following fields in its four modules.

##### 1\. Contact

![Contact module][11]

  * Name (String)
  * Email (Email)
  * Phone (String)
  * Address (String; _Multi-line_)



##### 2\. ContactDonation

![Corteza Donations app modules][12]

  * Contact (Record; link to **Contact**)
  * Donation (Number; _Prefix $_ and _Precision 2_)
  * Project (Record; link to **Project**)



##### 3\. Project

![Project module][13]

  * Name (String)
  * Description (String; _Multi-line_ and _Use rich text editor_)
  * Status (Select; with options _Planning_, _Active_, and _Finished_)
  * Start date (DateTime; _Date only_)
  * Website link (URL)
  * Donations total (Number; _Prefix $_ and _Precision 2_)
  * Project owner (User; _Multiple select_ and _Preset with current user_)



##### 4\. Notes

![Notes module][14]

  * Project (Record; link to **Project**)
  * Subject (String)
  * Note (String; _Multi-line_ and _Use rich text editor_)
  * File (File; _Single image_)



### Create relationships between modules

Practically every Corteza Low Code application consists of multiple modules that are linked together. For example, projects can have notes or donations can be assigned to different projects. The **Record** field type creates relationships between modules.

The **Record** field type's basic function is to link from module B back to module A. Records in module B are children of records in module A (you could say it's a 1-N relationship).

For example, in the Donations application, the module **Note** has a **Record** field that links to the module **Project**. The end user will see a **Select** field in a **Note** record with the value of the **Project** that the note pertains to.

To create this relationship in the Donations application, select the wrench icon in the **projectId** row:

![Wrench icon][15]

In the popup that opens, select the module the field will link to, the label end users will see, and which fields the end user can search on. 

![Setting query fields for search][16]

This creates a simple relationship that allows the **Project** to have **Notes**. A many-to-many relationship between modules is more complex. For example, the Donations application needs to support contacts who make multiple donations and donations that are assigned to different projects. The **ContactDonation** module sits in the middle to manage this.

This module has two fields of the **Record** type. For each, we need to select the correct module and set the label and query fields the user can search on. The Donations application needs the following to be set for the **Contact** and **Project** modules:

![Contact module field settings][17]

![Project module field settings][18]

This creates a many-to-many relationship between modules.

You've now set up a structure for the data in your application. The next step is to create the visual side of your app using Corteza's **Pages** feature. It's easier than you might expect, as you'll see in the third article in this series.

--------------------------------------------------------------------------------

via: https://opensource.com/article/19/10/corteza-low-code-data-structure

作者：[Lenny Horstink][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)

本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

[a]: https://opensource.com/users/lenny-horstink
[b]: https://github.com/lujun9972
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/metrics_lead-steps-measure.png?itok=DG7rFZPk (Green graph of measurements)
[2]: https://opensource.com/article/19/9/how-build-application-corteza-low-code-open-source-alternative-salesforce
[3]: https://latest.cortezaproject.org/compose/ns/donations/
[4]: https://opensource.com/article/19/8/corteza-open-source-alternative-salesforce
[5]: https://opensource.com/sites/default/files/uploads/corteza_donationsadminpanel.png (Open Corteza Low Code admin panel)
[6]: https://opensource.com/sites/default/files/uploads/corteza_donationsmenuadminpanel.png (Corteza Low Code admin panel menu)
[7]: https://www.libreoffice.org/discover/base/
[8]: https://opensource.com/sites/default/files/uploads/corteza_donationstmodules.png (Donations application modules)
[9]: https://eugdpr.org/
[10]: https://momentjs.com/docs/#/displaying/format/
[11]: https://opensource.com/sites/default/files/uploads/corteza_contactmodulefields.png (Contact module)
[12]: https://opensource.com/sites/default/files/uploads/corteza_contactdonationmodule.png (Corteza Donations app modules)
[13]: https://opensource.com/sites/default/files/uploads/corteza_projectmodule.png (Project module)
[14]: https://opensource.com/sites/default/files/uploads/corteza_notesmodule.png (Notes module)
[15]: https://opensource.com/sites/default/files/uploads/corteza_createrelationshipicon.png (Wrench icon)
[16]: https://opensource.com/sites/default/files/uploads/corteza_queryfieldsonsearch.png (Setting query fields for search)
[17]: https://opensource.com/sites/default/files/uploads/corteza_modulefieldsettings-contact.png (Contact module field settings)
[18]: https://opensource.com/sites/default/files/uploads/corteza_modulefieldsettings-project.png (Project module field settings)