{
    "table_name": "approval_step",
    "fields": [
        {"name": "id", "type": "varchar(32)", "not_null": true, "comment": "主键ID"},
        {"name": "workflow_id", "type": "varchar(32)", "not_null": true, "comment": "所属工作流ID"},
        {"name": "step_name", "type": "varchar(100)", "not_null": true, "comment": "步骤名称"},
        {"name": "step_number", "type": "int", "not_null": true, "comment": "步骤顺序号"},
        {"name": "approver_role", "type": "varchar(20)", "comment": "审批角色: role/user"},
        {"name": "approver_id", "type": "varchar(32)", "comment": "审批人ID"},
        {"name": "description", "type": "varchar(500)", "comment": "步骤描述"},
        {"name": "timeout_hours", "type": "int", "comment": "超时小时数"}
    ],
    "indexes": [
        {"name": "idx_step_workflow", "fields": ["workflow_id"], "type": "normal"},
        {"name": "idx_step_order", "fields": ["workflow_id", "step_number"], "type": "normal", "comment": "复合索引：按工作流和顺序查询"}
    ],
    "codes": [
        {"key": "role", "name": "角色审批"},
        {"key": "user", "name": "指定人审批"}
    ]
}