<association>
            <type>Activation</type>
          </association>
        </field>
        <field>
          <name>properties</name>
          <description>Extended configuration specific to this profile goes
            here.</description>
          <type>Properties</type>
          <association xml.mapStyle="inline">
            <type>String</type>

        </field>
        <field>
          <name>versioning</name>
          <version>1.0.0+</version>
          <association>
            <type>Versioning</type>
          </association>
          <description>Versioning information when this directory represents "groupId/artifactId" or "groupId/artifactId/version".</description>
        </field>
        <field>

	var emptyUser User
	var err error
	// belongs to
	err = DB.Model(&emptyUser).Association("Company").Delete(&user1.Company)
	AssertEqual(t, err, gorm.ErrPrimaryKeyRequired)
	// has many
	err = DB.Model(&emptyUser).Association("Pets").Delete(&user1.Pets)
	AssertEqual(t, err, gorm.ErrPrimaryKeyRequired)
	// has one
	err = DB.Model(&emptyUser).Association("Account").Delete(&user1.Account)
	AssertEqual(t, err, gorm.ErrPrimaryKeyRequired)

          <name>expressions</name>
          <description>The list of plugin parameter expressions described by this
            document.</description>
          <association>
            <type>Expression</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
      </fields>
      <codeSegments>
        <codeSegment>
          <version>1.0.0</version>

          <name>toolchains</name>
          <version>1.0.0+</version>
          <description>The toolchain instance definition.</description>
          <association xml.itemsStyle="flat">
            <type>ToolchainModel</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
      </fields>
    </class>
    <class>
      <name>ToolchainModel</name>
      <superClass>TrackableBase</superClass>

          <description></description>
          <association>
            <type>Parameter</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
        <field xdoc.separator="blank">
          <name>resolutions</name>
          <version>2.0.0+</version>
          <description></description>
          <association>
            <type>Resolution</type>

	if err := DB.Create(&user).Error; err != nil {
		t.Fatalf("errors happened when create: %v", err)
	}

	user.Company = Company{Name: "company-belongs-to-association"}
	user.Manager = &User{Name: "manager-belongs-to-association"}
	if err := DB.Save(&user).Error; err != nil {
		t.Fatalf("errors happened when update: %v", err)
	}

	var user2 User

          <description>A set of build extensions to use from this project.</description>
          <version>1.0.0+</version>
          <association xml.itemsStyle="flat">
            <type>CoreExtension</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
      </fields>
    </class>
    <class xml.tagName="extension">
      <name>CoreExtension</name>

	// ErrInvalidValue invalid value
	ErrInvalidValue = errors.New("invalid value, should be pointer to struct or slice")
	// ErrInvalidValueOfLength invalid values do not match length
	ErrInvalidValueOfLength = errors.New("invalid association values, length doesn't match")
	// ErrPreloadNotAllowed preload is not allowed when count is used
	ErrPreloadNotAllowed = errors.New("preload is not allowed when count is used")

         * same version index. Allowing the caller to pass in metadata from a previous deployment allows to re-establish
         * the association between the artifacts of the same project.
         */
        for (Iterator<? extends Metadata> it = metadatas.iterator(); it.hasNext(); ) {
            Metadata metadata = it.next();