{
    "summary": [
        {
            "name": "voucher_instance",
            "title": "代金券实例",
            "primary": ["id"],
            "catelog": "entity"
        }
    ],
    "fields": [
        {"name": "id", "title": "主键ID", "type": "str", "length": 32, "nullable": "no"},
        {"name": "template_id", "title": "模板ID", "type": "str", "length": 32, "nullable": "no"},
        {"name": "customer_id", "title": "客户ID", "type": "str", "length": 32, "nullable": "no"},
        {"name": "code", "title": "唯一券码", "type": "str", "length": 64, "nullable": "no"},
        {"name": "status", "title": "状态", "type": "str", "length": 16, "nullable": "no", "default": "unused"},
        {"name": "face_value", "title": "面值", "type": "double", "length": 10, "dec": 2, "nullable": "no"},
        {"name": "actual_deducted", "title": "实际抵扣金额", "type": "double", "length": 10, "dec": 2, "nullable": "yes"},
        {"name": "valid_from", "title": "生效时间", "type": "datetime", "nullable": "no"},
        {"name": "valid_to", "title": "过期时间", "type": "datetime", "nullable": "no"},
        {"name": "issued_at", "title": "发放时间", "type": "datetime", "nullable": "no"},
        {"name": "used_at", "title": "使用时间", "type": "datetime", "nullable": "yes"},
        {"name": "order_id", "title": "使用的订单ID", "type": "str", "length": 64, "nullable": "yes"},
        {"name": "source", "title": "来源", "type": "str", "length": 32, "nullable": "yes"},
        {"name": "remark", "title": "备注", "type": "str", "length": 255, "nullable": "yes"},
        {"name": "created_at", "title": "创建时间", "type": "timestamp", "nullable": "no"},
        {"name": "updated_at", "title": "更新时间", "type": "timestamp", "nullable": "no"}
    ],
    "indexes": [
        {"name": "idx_instance_code", "idxtype": "unique", "idxfields": ["code"]},
        {"name": "idx_instance_customer", "idxtype": "index", "idxfields": ["customer_id"]},
        {"name": "idx_instance_template", "idxtype": "index", "idxfields": ["template_id"]},
        {"name": "idx_instance_status", "idxtype": "index", "idxfields": ["status"]},
        {"name": "idx_instance_valid_to", "idxtype": "index", "idxfields": ["valid_to"]}
    ],
    "codes": [
        {
            "field": "template_id",
            "table": "voucher_template",
            "valuefield": "id",
            "textfield": "name"
        },
        {
            "field": "status",
            "table": "appcodes_kv",
            "valuefield": "k",
            "textfield": "v",
            "cond": "parentid='voucher_instance_status'"
        }
    ]
}