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The FHIR SQL Builder

The FHIR SQL Builder, or Builder, is a sophisticated projection tool used to create custom SQL schemas using data in an HL7® FHIR® repository without moving the data to a separate SQL repository. The Builder is designed specifically to work with FHIR repositories and multi-model databases in InterSystems products.

The objective of the Builder is to enable data analysts and business intelligence developers to work with FHIR using familiar analytic tools, without having to learn a new query syntax. FHIR data is encoded in a complex directed graph and cannot be queried using standard SQL syntax. A graph-based query language, FHIRPath, is designed to query FHIR data, but it is non-relational. Enabling a data steward to create a customized SQL projection of their FHIR repository, using tables, columns, and indexes, the Builder makes it possible for data analysts to query FHIR data without the complexity of learning FHIRPath or the FHIR search syntax.

The following diagram shows the relationships between the Builder and other components in InterSystems products.

The Builder communicates with FHIR repositories and the client UI to produce SQL projection tables

The Builder analyzes a FHIR repository to generate summary information, including the types of resources, elements, and values it contains, as well as the number of each type of resource. You decide which FHIR resources and elements to include in your custom SQL projection and how to map them.

Schema Generation Overview

To generate a schema the main actions are:

  1. Analyze the FHIR repository.

  2. Present the analysis to the user.

  3. Use decisions made by the user to create the required tables.

The analysis process needs to examine enough of the repository to provide useful information, while limiting how much it examines to conserve time and resources. You can make decisions that influence this balance when configuring the analysis task. You can also configure the task to run at a time when there is less demand for computing resources.

Configuration

If your license key is in place before the installation of your InterSystems product finishes, the Web Applications that implement the Builder will already be enabled. Otherwise, you will need to manually enable them. On the instance that is running the Builder:

  1. In the Management Portal, go to System Administration > Security > Applications > Web Applications.

  2. On the Web Applications page, enable the applications /csp/fhirsql and /csp/fhirsql/api/ui by selecting the name of the application, which opens the Edit Web Application page.

  3. On the General tab of the Web Application page, click the Enable Application check box and then click Save.

The FHIR SQL Builder is designed to work with FHIR repositories across different instances of InterSystems products. On each instance that runs a FHIR server, follow the steps above to enable /csp/fhirsql/api/repository. Only one instance should have the /csp/fhirsql/api/ui API enabled, but any number of instances can have the /csp/fhirsql/api/repository API enabled.

Once the applications have been properly enabled, you will be able to open the Builder at http://hostname:portnumber/csp/fhirsql/index.html#/, where hostname is the name of the host of your instance (this can be localhost) and portnumber is the port number of your instance.

Users that access the Builder must be assigned to one of the preconfigured FHIR SQL Builder roles:

Users who are not assigned one of these roles encounter a 403 error when they attempt to access the FHIR SQL Builder. For more information about assigning roles to users, see “Manage Roles”Opens in a new tab in RolesOpens in a new tab.

Starting the FHIR SQL Builder application brings you to the home page. The work area is divided into sections which let you configure the Analyses, Transformation Specifications, and Projections of your repository.

Analyze the FHIR Repository

The goal of analyzing your FHIR Repository is to summarize the available structural relationships, constituent elements, and embedded collections of the repository. It forms the basis for defining a transformation specification by outlining how various elements are related to one another and providing a range of values you can expect for a given element. The analysis task does not need to look at every record in the repository; is up to you to decide the size of the sample that you will analyze.

To configure an analysis, click New on the right side of the Analyses section to open the New FHIR Analysis dialog. Fill out this dialog as follows:

  • FHIR repository – You can select a repository from the drop-down list or create a new repository by clicking New to the right of the field to open the New FHIR Repository Configuration dialog. Fill out this dialog as follows:

    • Name – Enter a name for the repository.

    • Host – Enter the DNS name or IP address of the host where the repository you wish to analyze is hosted. If the Builder UI and the repository are on the same instance, you can use localhost.

    • Port – Enter the port used to access the repository.

    • SSL Configuration (optional) – If you are using SSL, select the SSL configuration you want to use. For information about creating a new SSL configuration, refer to “Create or Edit a TLS Configuration”Opens in a new tab in About ConfigurationsOpens in a new tab.

    • Credentials – Select credentials from the drop-down list or create new credentials by clicking the New button to the right of the field to open the New Credentials dialog. Fill out this dialog as follows:

      • Name – Enter a name for this credentials object.

      • Username – Enter the username. This must be the name of a User on the current instance. To see a full list of the available names, open the Management Portal and navigate to System Administration > Security Management > Users.

      • Password – Enter the password.

      • Click Save to return to the New FHIR Repository Configuration dialog.

      Important:

      The user account you specify with a FHIR Repository must also be assigned to the FSB_Admin role.

    • FHIR Repository URL – Select a repository from the drop-down list. When the values entered for Name, Host, Port, and Credentials establish a valid connection, this field provides a list of available FHIR repositories.

    • Click Save to return to the New FHIR Analysis dialog.

  • Selectivity Percentage – Limits analysis to a percentage of the FHIR repository. If used, Maximum Records cannot be used.

  • Maximum Records – Limits analysis to a maximum number of records in the FHIR repository. If used, Selectivity Percentage cannot be used.

  • Defer Start of Task – Select this check box to run the analysis task at a later point in time. If selected, enter a Start Date and a Start Time.

  • Click Launch Analysis Task to start analyzing the FHIR repository.

You will see the newly started analysis on the list of analyses on the Builder home page. Columns provide the following information:

  • FHIR Repository – The name you provided when configuring the analysis.

  • Start Time – The date and time the analysis started.

  • Last Modified – The date and time you last modified the analysis.

  • Status – The possible values are: Running, Stopping, Stopped, Completed, and Errored.

  • Total Resources – The number of FHIR records analyzed.

  • Percent Complete – The amount of the analysis completed as a percentage of the anticipated total.

  • Actions – Provides buttons you can use to control the progress of the analysis.

    • generated description: builder pause-button Resume – Resumes running a paused analysis.

    • generated description: builder resume-button Pause – Pauses a running analysis.

    • generated description: builder delete-button Delete – Deletes the analysis of the repository. An analysis cannot be deleted if a Transformation Specification depends on it.

Creating a New Transformation Specification

Once the FHIR Repository analysis is complete, you can use the resulting information to create a transformation specification. A transformation specification structures the table schemas it generates and determines which resources and elements should be included in the projection. Transformation specifications can also be exported, imported, and copied; see Exporting, Importing, and Copying a Transformation Specification for more information.

To create a new Transformation Specification, click the New button on the right side of the Transformation Specifications section to open the New Transformation Specification dialog. Fill out this dialog as follows:

  • Name – Provide a unique name for this specification.

  • Analysis – Select a FHIR Repository analysis from the drop-down list. Analyses are identified by the repository name and the date the analysis was created.

  • Description (Optional) — Provide a brief description of the transformation specification.

  • Click Create Transformation Specification to open the Edit Transformation Specification page.

The page opens listing resources and elements in the FHIR repository and their counts. Selecting a resource, such as Patient, shows the elements in that resource.

The structure presented by the analysis reflects the often deeply nested structure of the FHIR repository. Elements are:

  • primitives, such as string, boolean, date, or number

  • objects, which contain properties that are primitives, objects, or collections

  • collections, which contain primitives, objects, or collections

Resources are structured like trees, and selecting a node (which represents either an object or a collection in the repository) opens the properties it contains below it. Leafs (which represent primitive elements) across the repository may have identical names, like “code.” As such, it is best to refer to a primitive element in the tree by the full path through the nodes from the parent resource to the child leaf (for example, “AllergyIntolerance.code.coding.code” as opposed to “Patient.code.coding.code”).

Adding a Primitive Element to the Schema

Select a primitive element to open a panel that allows you to add the element to the schema. For primitives, such as strings or numbers, you can click Show Histogram to view a histogram of the unique values in the repository. You can edit the name of the column that will appear in the table by editing the Column name field. Select the check box label Index if you would like to add an index on this column in the table. For information regarding which elements you may want to add an index to, see “What to IndexOpens in a new tab” in Optimizing Query PerformanceOpens in a new tab.

Finally, click Add To Projection to add the element to the Projection.

The Currently Selected Items table on the edit page shows the current state of the schema. It has columns the following columns:

  • Table – The name of the table the added column is for. You can add elements from multiple different resources to a schema in a Transformation Specification; theses elements will appear in the tables as specified by the values in this column.

  • Column – The name of the column that will appear in the table.

  • Type – The datatype of the contents of the column.

  • Index – Indicated whether an index will be created for the column.

  • Actions – Provides buttons you can use to edit or delete the specific element.

    • generated description: builder edit-button Edit – Opens the panel that you used to add the element to the schema, enabling you to edit your preferences for this column, including setting filters, in the schema.

    • generated description: builder delete-button Delete – Deletes the column specified by the from the schema.

You can add as many elements to the schema as needed. Click Done to return to the home page, where you will find the new specification listed.

Adding Data from Collections to the Schema

Some elements have collections associated with them. Selecting a collection will bring up a selection panel where all the elements at the bottom node of the collection are listed in rows. An example, using the Identifier collection of a Patient, is below. Note that this particular collection has both a object and primitive elements within it.

A list of resources on the left and on the right a window showing elements that may be added to the projection

Click the check boxes next to the primitive elements you would like to add to the projection. When adding data from a collection in this manner, the Builder will automatically create a subtable for this data and it will not be included in the table of the parent resource. The name of the table is identified by the Subtable name field, which you can edit. The rows of this table correspond to individual entries of the collection and the columns are the elements of the collection you have specified, plus some special columns that help identify what resource they came from and where in the collection they appear.

However, it is sometimes desirable to have data from a collection stored within a table representing the resource it came from and not in a subtable. To do so, you should navigate to a primitive element you would like to add by clicking through the collection and selecting Add to Projection. However, this action will automatically populate the column with the value of the first element of the collection. As this element is likely arbitrary, it is not recommended to leave the column as such. Instead, you should use the Filter option.

The Filter option allows you to choose specific data from a collection to include in the projection. From any leaf in the resource’s tree, you are able to click on a preceding node in the full path, except for the initial resource you are drawing from (for example, the Patient resource name) or the leaf itself (for example, the terminal display node). In the example below, the filter has been created by clicking on coding; it is usually best practice to set a filter on the deepest node of the resource tree. You can set conditions to determine which fields to show in the projection. The filter is set to include the display element of the item in the collection where the code element equals “SS.”

A filter on the coding node of the Patient resource tree that appeared by clicking coding

The table projected by this transformation will show the display element of the coding objects that had a code of “SS.” However, if the filter was set on code elements equal to “MR,” the table will show the display element of the coding objects that had a code of “SS.”

You can use the filter option with different operations; it is not limited to use with equals. Additional operations include greater than, less than or equal to, greater than or equal to, exists, like regex, resolves to type, and more. You should configure a filter that fits your needs.

You can also add multiple filters for a particular element to finely tune which data appears in your table; however, multiple filters cannot be set on the same tier of a path. Additionally, you cannot set a filter on elements of a subtable; instead, you must set a filter on the subtable itself, which will then include only the elements that meet the filtered condition.

Note that in some cases, a collection may not include an object that matches the filter you have specified. In these cases, the rows that do not contain such elements will not have any data in that column.

Adding an Object to the Schema

To add an element of an object associated with the resource, click through the object’s elements until you get to a primitive element as described in “Adding a Primitive Element.”

You are allowed to set a filter on objects, as you can with collections. In this case, the filter is most useful as a method to remove any values from the table that do not match a certain criteria. In the example below, the filter is used to show the start element of a CarePlan when the end element is January 31, 1969. In the resultant CarePlan table, rows that did not end on that date will not have any data in the start column.

A filter on the period node of the care plan resource tree that appeared by clicking period

Viewing Transformation Specifications

On the main FHIR SQL Builder page, you will see your Transformation Specifications listed under the header. Columns in the listing provide the following information:

  • Name – The name of this specification.

  • Analysis – The analysis used to create this specification.

  • Description – The description of the transformation specification as defined when it was initially created.

  • Last Modified – The date and time the specification was last modified.

  • Actions – Provides buttons you can use to manage the specification.

    • generated description: builder edit-button Edit – Opens the Edit Transformation Specification page.

    • generated description: builder copy-button Copy – Opens the Copy Transformation Specification dialog box to create a new specification identical to this one. For more information, see “Copying a Transformation Specification.”

    • generated description: builder export-button Export – Downloads a JSON file of the transformation specification that can be shared and imported. For more information, see “Exporting a Transformation Specification.”

    • generated description: builder delete-button Delete – Deletes the transformation specification. A transformation specification cannot be deleted if a projection depends on it.

Exporting, Importing, and Copying a Transformation Specification

Transformation specifications can be exported, imported, and copied. Imported and copy transformation specifications can be further edited to further customize them.

Exporting a Transformation Specification

Transformation specifications can be exported to allow you to share these specifications with other users or instances, where they can be imported. To export a transformation specification, click the Export icon on the row of the Transformation Specifications table on the home page. A JSON file will be downloaded to you local file system. This file can be shared and imported into other systems.

Importing a Transformation Specification

A previously exported transformation specification can be re-imported on the same system or imported on another system.

To import a transformation specification, click on the Import button on the Transformation Specifications table on the home page. You will then be prompted to select the JSON transformation specification file that you want to import from your file system. When a valid file is selected, the Import Transformation Specification dialog will open with the following fields:

  • Name – The name of the imported transformation specification. This will be pre-populated from the JSON file, but can be edited here.

  • Analysis – The completed FHIR repository analysis from which to build the transformation specification. The analysis should have resources that correspond with the resources in the transformation specification.

  • Description – A brief description to help distinguish between specifications. This will be pre-populated from the JSON file, but can be edited here.

Click the Import button to complete the import process. The new specification will appear in the Transformation Specifications table.

Copying a Transformation Specification

Any existing transformation specification can be copied to create a new specification with a new name and description. This new specification can be further modified and used, independent of its original specification.

To copy a transformation specification, click the Export icon on the row of the Transformation Specifications table on the home page. Fill out the dialog box as follows:

  • Name – The name of this new specification. This will come pre-populated as “Copy of transformation,” where transformation is the name of the transformation specification that is being copied.

  • Description – A brief description to help distinguish between specifications. Like the Name field, this will come pre-populated as “Copy of transformation,” where transformation is the name of the transformation specification that is being copied.

Click the Copy button to complete the import process. The new specification will appear in the Transformation Specifications table.

Create the Projection

The final step is to create a data Projection. Click New on the right side of the Projections section to open the New Projection dialog. Fill out this dialog as follows:

  • FHIR Repository – The repository to use for this projection. This drop-down menu includes the names of the repositories added when creating a new Analysis.

  • Transformation Specification – The specification used to create this projection.

  • Package Name – A name for the package the SQL tables will be put in.

  • Click Launch Projection to create the projection.

Once you have created the projections, columns provide the following information:

  • FHIR Repository – The name of the FHIR repository on which the projection is based.

  • Transformation Specification – The Transformation Specification that the Projection is based on.

  • Namespace – The namespace that the Projection will be stored in.

  • Package Name – The package that the Projection will be stored in.

  • Actions – Provides buttons you can use to manage the specification.

    • generated description: builder link-button Link – Opens the System Explorer > SQL page of the Management Portal.

    • generated description: builder update-button Update – Updates the Projection to reflect changes in the underlying Transformation Specification.

    • generated description: builder delete-button Delete – Deletes the Projection.

Clicking the Link button opens a page in the Management Portal. Enter the package name you specified when creating the Projection into the Filter box on the upper left side of the screen. The projections you have created will appear under Tables on the left.

Drag the table to the Execute Query tab, as shown:

A user drags the patient schema into the execute query tool in the management portal

Then execute the query. The table will appear below.

Example table that results from using the Builder

Note:

A system task called IndicesTask will be created on the FHIR Repository if the system were to shut down while indexes were being built. This task will resume building indexes when the system starts up again.

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