if (item instanceof SQLIdentifierExpr) {
String columnName = ((SQLIdentifierExpr) item).getName();
String leftTable = (String) x.getLeft().getAttribute(ATTR_TABLE);
String rightTable = (String) x.getRight().getAttribute(ATTR_TABLE);
if (leftTable != null && rightTable != null) {
Relationship relationship = new Relationship();
relationship.setLeft(new Column(leftTable, columnName));
relationship.setRight(new Column(rightTable, columnName));
relationship.setOperator("USING");
relationships.add(relationship);
}
if (leftTable != null) {
addColumn(leftTable, columnName);