带有嵌套模式数组的 avro答案

【问题标题】：avro with an array of nested schema带有嵌套模式数组的 avro
【发布时间】：2016-10-23 09:05:03
【问题描述】：

我试图在 apache avro 中表示“订单”及其相关条目。有关架构，请参见下文。尝试在 Eclipse 中构建它时出现以下错误。任何帮助表示赞赏。

[ERROR] Failed to execute goal org.apache.avro:avro-maven-plugin:1.8.1:schema (default) on project avrosample: Execution default of goal org.apache.avro:avro-maven-plugin:1.8.1:schema failed: Undefined name: "com.company.domain.entry" -> [Help 1]

**Schema For Entry:**
{"namespace": "com.company.domain",
 "type": "record",
 "name": "entry",
 "fields": [
     {"name": "id", "type": "long"},
     {"name": "description",  "type": "string"},
     {"name": "quantity", "type: “int”}

 ]
}

**Schema for Order:**
{"namespace": "com.company.domain",
 "type": "record",
 "name": "order",
 "fields": [
     {"name": "id", "type": "long"},
     {"name": "date",  "type": "long"},
     {"name": "entries", "type": {"items": "array", "items": "com.company.domain.entry"} }}

 ]
}

【问题讨论】：

标签： schema avro

【解决方案1】：

如果我没记错的话，您不能以这种方式将 Entry-schema 链接到 Order-schema。为什么不使用联合模式来代替 Order？像这样的：

{
  "type": "record",
  "name": "Order",
  "namespace": "com.company.domain",
  "fields": [
    {
      "name": "id",
      "type": "long"
    },
    {
      "name": "date",
      "type": "long"
    },
    {
      "name": "entries",
      "type": {
        "type": "array",
        "items": {
          "type": "record",
          "name": "Entry",
          "fields": [
            {
              "name": "id",
              "type": "long"
            },
            {
              "name": "description",
              "type": "string"
            },
            {
             "name": "quantity",
              "type": "int"
            }
          ]
        },
        "java-class": "java.util.List"
      }
    }
  ]
}

【讨论】：