I'm having issues attmepting to set up an Entity Record Type based on an exi

I'm having issues attmepting to set up an Entity Record Type based on an existing mySQL table.

I manually created a data type based on the database (is there a way to import the structure from mySQL instead?). I then exported the XSD and manually updated that file to indicate that the a_id field was the primary field and would be auto-incremented. I then removed the original data type and attempted to import the new XSD file, but get a message that

The element type "xsd:sequence" must be terminated by the matching end-tag "</xsd:sequence>"

Although the XSD file definitely has both of those tags:

<xsd:schema
targetNamespace="obmdev.appiancloud.com/.../"
xmlns:types150="obmdev.appiancloud.com/.../" xmlns:xsd="www.w3.org/.../XMLSchema">
<xsd:complexType name="training">
<xsd:sequence>
<xsd:element name="a_id" nillable="true" type="xsd:int"/>
                    <xsd:annotation>
                    <xsd:appinfo source="appian.jpa">...

OriginalPostID-76791

OriginalPostID-76791