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)

	RightJoin JoinType = "RIGHT"
)

type JoinTarget struct {
	Type        JoinType
	Association string
	Subquery    Expression
	Table       string
}

func Has(name string) JoinTarget {
	return JoinTarget{Type: InnerJoin, Association: name}
}

func (jt JoinType) Association(name string) JoinTarget {
	return JoinTarget{Type: jt, Association: name}
}

            <type>Repository</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
        <field>
          <name>pluginRepositories</name>
          <version>1.3.0+</version>
          <description>
            The lists of the remote repositories for discovering plugins.
          </description>
          <association>
            <type>Repository</type>

      <fields>
        <field>
          <name>lifecycles</name>
          <version>1.0.0+</version>
          <association xml.itemsStyle="flat">
            <type>Lifecycle</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
      </fields>
    </class>
    <class>
      <name>Lifecycle</name>
      <version>1.0.0+</version>

          <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>

          </description>
          <association>
            <type>License</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
        <field xdoc.separator="blank">
          <name>developers</name>
          <version>3.0.0+</version>
          <description>Describes the committers of a project.</description>
          <association>
            <type>Developer</type>

          <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>

        </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>

      <fields>
        <field>
          <name>exportedPackages</name>
          <version>1.0.0</version>
          <association>
            <type>String</type>
            <multiplicity>*</multiplicity>
          </association>

          <description>
            Remote resources that are contained in a remote resources bundle.
          </description>
          <association>
            <type>String</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
        <field>
          <name>sourceEncoding</name>
          <version>1.1.0</version>
          <description>