{
    "summary": [
        {
            "name": "exchange_rate",
            "title": "汇率表",
            "primary": ["id"]
        }
    ],
    "fields": [
        {
            "name": "id",
            "title": "id",
            "type": "str",
            "length": 32
        },
        {
            "name": "from_currency",
            "title": "源币种",
            "type": "str",
            "length": 3
        },
        {
            "name": "to_currency",
            "title": "目标币种",
            "type": "str",
            "length": 3
        },
        {
            "name": "buy_rate",
            "title": "买入价",
            "type": "float",
            "length": 14,
            "dec": 6
        },
        {
            "name": "sell_rate",
            "title": "卖出价",
            "type": "float",
            "length": 14,
            "dec": 6
        },
        {
            "name": "mid_rate",
            "title": "中间价",
            "type": "float",
            "length": 14,
            "dec": 6
        },
        {
            "name": "effective_date",
            "title": "生效日期",
            "type": "date"
        },
        {
            "name": "updated_at",
            "title": "更新时间",
            "type": "datetime"
        }
    ],
    "indexes": [
        {
            "name": "idx_currency_pair_date",
            "idxtype": "unique",
            "idxfields": ["from_currency", "to_currency", "effective_date"]
        }
    ],
    "codes": [
        {
            "field": "from_currency",
            "table": "currency",
            "valuefield": "id",
            "textfield": "name"
        },
        {
            "field": "to_currency",
            "table": "currency",
            "valuefield": "id",
            "textfield": "name"
        }
    ]
}