{
    "table_name": "approval_task",
    "fields": [
        {"name": "id", "type": "varchar(32)", "not_null": true, "comment": "主键ID"},
        {"name": "instance_id", "type": "varchar(32)", "not_null": true, "comment": "所属实例ID"},
        {"name": "step_id", "type": "varchar(32)", "not_null": true, "comment": "审批步骤ID"},
        {"name": "assignee_id", "type": "varchar(32)", "comment": "审批人ID"},
        {"name": "status", "type": "varchar(20)", "comment": "状态: pending/approved/rejected"},
        {"name": "comment", "type": "varchar(1000)", "comment": "审批意见"},
        {"name": "org_id", "type": "varchar(32)", "comment": "组织ID"},
        {"name": "assigned_at", "type": "timestamp", "comment": "分配时间"},
        {"name": "completed_at", "type": "timestamp", "comment": "完成时间"}
    ],
    "indexes": [
        {"name": "idx_task_instance", "fields": ["instance_id"], "type": "normal"},
        {"name": "idx_task_assignee", "fields": ["assignee_id"], "type": "normal"},
        {"name": "idx_task_status", "fields": ["status"], "type": "normal"}
    ],
    "codes": [
        {"key": "pending", "name": "待审批"},
        {"key": "approved", "name": "已通过"},
        {"key": "rejected", "name": "已驳回"}
    ]
}