Choose a Design Approach

There are three ways of connecting your form to your database.  recommends that you understand read and understand each approach carefully before moving forward with form design in order to determine the most efficient approach, and prevent the need to redesign later. This table can help you decide which design approach to use based on your business requirements.

Design Methods

• Create a form from an XML schema. In this case, the controls will be automatically created for you based on the XML schema definitions, and you can use the Doc URI approach.
• Drag and drop controls from the designer palette. You will have all control properties available in the designer, but you will only be able to use the Business Rule approach for database integration.
• You may also use a combination of the two methods and create some controls from schema and others from palette.

The Doc URI Approach

This is the recommended approach because it involves automatically generating controls in your form based on the database table you will be integrating with, and using the no-code Document Action: Manually Set Doc URIs to perform CRUD Operations on your database. The Doc URI Approach must be used with the "from an XML schema" design method. Follow these steps.

1. Generate the XML Schema based on your SQL Statements that allows you to add form controls that match your database table columns.
2. Add Form Controls from Schema in the form/workflow designer.
3. Set Doc URIs to automatically read from and write to the database.

Generate the XML Schema

You can use the database connector to generate the schemas you will need to use in your  form. To fetch the schema, type a URI in the browser that looks like the example below.  This is almost identical to the query we used to test the connector, but it tells the connector to GET the schema instead.

http://<host>:<port>/database/<queryset name>/<query name>/schema?<template name>=<template value>

If your SQL Retrieve statement includes template variables, you’ll need to add the variable names as shown below. The schema itself does not require variables but the connector fetches the schema the same way it fetches data for the retrieve statement, so the connector expects the template names and values in the URI.

For the example we've been using so far, point your browser to the url: http://localhost:8082/database/BIRT/allCustomers/schema?customerNumber=237

You should get an XML schema similar to the following:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<xsd:schema xmlns="http://www.frevvo.com/database/allCustomers" xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.frevvo.com/database/allCustomers">
  <xsd:annotation>
    <xsd:appinfo xmlns:f="http://www.frevvo.com/database/" f:connectorVersion="2.5.3-r30969" f:digest="4f2c46033e8ff5a221ab7106c4003833157e7f6a" f:last-modified="Sat Aug 19 19:06:45 EDT 2017" source="http://www.frevvo.com/database/"/>
  </xsd:annotation>
  <xsd:element name="allCustomers">
    <xsd:annotation>
      <xsd:appinfo xmlns:f="http://www.frevvo.com/database/" f:autoCreate="true" f:autoDelete="false" f:enabled="true" source="http://www.frevvo.com/database/"/>
    </xsd:annotation>
    <xsd:complexType>
      <xsd:sequence>
        <xsd:element maxOccurs="unbounded" minOccurs="0" name="row">
          <xsd:complexType>
            <xsd:sequence>
              <xsd:element name="customerNumber" type="xsd:int"/>
              <xsd:element name="customerName">
                <xsd:simpleType>
                  <xsd:restriction base="xsd:string">
                    <xsd:maxLength value="50"/>
                  </xsd:restriction>
                </xsd:simpleType>
              </xsd:element>
            </xsd:sequence>
          </xsd:complexType>
        </xsd:element>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>
</xsd:schema>

Save the schema as an .xsd file in your file system. 

If you have multiple queries in your configuration file, you have two options:

1. Generate the schemas for an entire queryset.  When there are a large number of queries in the configuration.xml, getting the schemas for all of them eliminates having to create a schema one by one for each query. The queryset schema can be uploaded to your project one time and then you can add the relevant schema elements to your forms/workflows as you need them.

   Code Block
   http://<server>:<port>/database/BIRT/schema

2. Generate a schema for each query.

   Code Block
   http://<server>:<port>/database/BIRT/allCustomers/schema

Add Form Controls from Schema

To use your schema, first upload the schema in the Schemas tab of your  Project. Visit the Using Your Schema documentation for detailed steps.

Next, open your form or workflow and add one or more elements from schema in the Data Sources panel. This allows you to generate controls from the schema elements that map to your database tables. See the Data Sources chapter for detailed steps.

Set Document URI Properties

Still using the customers example, assume the Document URI for the schema customers is: 

http://localhost:8082/database/myStore/customers?customerId={customerId}

If you choose the Write method to be POST, the SQL statement that will be executed is:

<create>               
 <statement>
 INSERT into customers (customerId,firstname,lastname)      
 VALUES ({customerId},'{firstname}','{lastname}')
 </statement>          
</create>

At run time, the values of {customerId}, {firstname} and {lastname} will be replaced by the values of the respective form controls.

What happens at run Time?

Let's assume that you defined the same Document URI in the Read and Write URI fields in the wizard for a schema in the form, a GET Read Method and a PUT Write Method.

When a user loads your form, a GET request for that URI will be sent to the database connector. That will cause the database connector to execute the retrieve operation for the query specified in the URI, take the result of the SQL execution and transform it to XML. The database connector will then return the resulting XML back to the form which will be initialized with the contents of the XML file.

When the user submits the form, the same URI will be executed but now with the PUT (or POST) method. The database connector will than execute the update operation identified by that URI.

Customizing the XML Schema

The schema you retrieve from your database will be relatively generic.  As a result the controls you generate from this database schema might need some tweaking to suit the specific needs of your form. You can modify a control’s behavior by making changes to the schema after you have retrieved it. Please visit the Data Sources chapter for more details on modifying the controls generated from schema..

If you have already uploaded the schema to , you can still make the changes and update the schema.

Post via Web Hook 

In a workflow, the Doc URI writes to the database at the end of the workflow, after the final step is submitted. Perhaps you want to post to the database mid-workflow. You could use the Business Rule Approach, or for a no-code approach, you can simply use the same URL you would use for the Doc URI POST in a Web Hook.

1. In Workflow Editing Mode, click the + icon after the step that should post data to your database.
2. Select Add web-hook (HTTP POST)
   
3. Enter the Database URL for the query that contains your create statement, e.g. http://localhost:8082/database/products/allProducts. Be sure to check the Data checkbox. Click Submit.
   

You will see the Web Hook displayed in your workflow diagram, and you can edit it at any time. The Database Connector will run the create statement to post data after the user clicks Continue on Step 1.

The Business Rule Approach

It is also possible to write business rules to perform CRUD operations. Business rules tend to be more complex and time-intensive to implement. The Business Rule Approach can be used with either the "from palette" or the "from an XML schema" design method. This approach is discussed in further detail with several examples in the following documentation:

• The Database Connector Tutorial (recommended)
• Business Rules HTTP Methods
• Rule Examples for the Database Connector

Dynamic Options