Importing source and target schemas

Schemas define the structure of the data both concretely (e.g. XML schema, database schema) and conceptually (description in terms of classes/types, properties and relations, e.g. UML). HALE’s main job is to abstract a conceptual schema from a concrete schema and to assist the user in mapping concepts from a source schema to a target schema.

In this training, source schemas will be inferred from a PostGIS database, while target schemas will be extracted from XSD files.

Importing the source schema

To import the source schema, follow these steps:

  1. Make sure the PostgreSQL server is running.

    Note

    If it’s not running, start it by double clicking on the start_postgis.bat batch script (windows) or type in the terminal sudo service postgresql start (linux).

  2. Select File → Import → Source schema… from the menu bar on top.

  3. A wizard will open. On the first page of the wizard, click on the From Database (JDBC) tab and populate the form fields as shown in the figure below.

  • Host(:Port): localhost:5434

  • Database: hale_tutorial

../../_images/hale_import_schema_jdbc.png

  1. The next page will ask you for credentials to access the database. Enter hale_tutorial as both User and Password.

  • User: hale_tutorial

  • Password: hale_tutorial

../../_images/hale_import_schema_auth.png

  1. After the schema has been imported, the Schema Explorer view should look like the figure below:

../../_images/hale_import_schema_explorer.png

Note that HALE created a new type for each table in the database.

  1. Not all source types are relevant for the mapping we want to create. Select Edit → Edit mapping relevant source types from the menu bar and uncheck the irrelevant types, as shown in the figure below.

    source_rel

  2. Click finish, and now the Source section in the Schema Explorer view should show only the selected types.

Importing the target schema

See this introductory part for a detailed description of the meteo target schema.

Note

Before importing the target schema, make sure GeoServer is actually running by visiting the URL http://localhost:8083/geoserver. If it’s not running start it by double clicking on the tomcat_start_1.bat batch script. This step also requires internet connectivity.

To import the target schema, follow these steps:

  1. Select File → Import → Target schema… from the menu bar on top.

  2. A wizard will open. On the first page of the wizard, click on the From URL tab, copy the URL http://localhost:8083/geoserver/www/meteo/meteo.xsd in the Source URL field and click on the Detect button.

  3. The Content type option should display XML schema. Click on the Finish button.

import_schema_url

  1. After the schema has been imported, the Schema Explorer view should look like the figure below.

import_schema_expl