试用了一下Windows下的OpenSystemArchitect

https://www.codebydesign.com/SystemArchitect/Documentation/

容易卡住，然后死机器，还需要探索

初步成果，尝试了两张表，主键引用，生成的PG,SQL如下

-- +---------------------------------------------------------
-- | MODEL       : acctloan
-- | AUTHOR      : ccy
-- | GENERATED BY: Open System Architect
-- +---------------------------------------------------------
-- | WARNING     : Review before execution
-- +---------------------------------------------------------

-- +---------------------------------------------------------
-- | CREATE
-- +---------------------------------------------------------
CREATE TABLE business_contract
(
  serialno ,
  customername ,
  PRIMARY KEY (serialno)
);
CREATE TABLE acct_loan
(
  serialno ,
  contractserialno ,
  PRIMARY KEY (serialno)
);
CREATE TABLE
(

) INHERITS ();
;
ALTER TABLE acct_loan ADD CONSTRAINT FK_BC_SERIALNO
  FOREIGN KEY ( contractserialno )
   REFERENCES business_contract ( serialno )
    NOT DEFERRABLE;