使用JSONiq插入JSON

我们正在编写一个JSONiq查询，将新属性插入JSON并从查询返回更新的JSON

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

查询：

jsoniq version "1.0";
let $users := {
  "name" : "Deadbeat Jim",
  "address" : "1 E 161st St, Bronx, NY 10451",
  "risk tolerance" : "high"
} 
insert json {"status" : "credit card declined"} into $users
return $users

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

users

保存输入json，我们正试图使用JSONiq insert命令添加一个属性，如JSONiq文档中所述

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

我们得到以下例外：

java.lang.RuntimeException: (no URI):13,1: static error [err:XPST0003]: invalid expression: syntax error, unexpected expression (missing comma "," between expressions?)

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

问题：

jsoniq version "1.0";
let $users := {
  "name" : "Deadbeat Jim",
  "address" : "1 E 161st St, Bronx, NY 10451",
  "risk tolerance" : "high"
} 
insert json {"status" : "credit card declined"} into $users
return $users

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

这个问题正确吗？如果没有，如何使其在语法/逻辑上正确

有没有关于JSONiq的好的在线资源和例子

---

这是使用JSONiq实现json更新的方法。我们需要使用copy modify return子句：

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

---

希望这可能对某些人有所帮助

以下是一些更多的解释：

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

JSONiq更新的工作方式与XQuery更新的工作方式相同。JSONiq更新是声明性的：JSONiq更新程序除了返回数据模型中的空序列外，还返回一个被称为“待更新列表”（PUL），它是应用于某些文档的更新（删除、替换、重命名、插入等）列表

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

JSONiq更新具有快照语义，这意味着在对主表达式求值期间，没有副作用。相反，在计算PUL后，引擎可能会将PUL指定的更改传播到底层存储（例如磁盘上的文件或文档存储）

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

该问题示例的语法正确版本为：

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

jsoniq version "1.0";
let $users := {
  "name" : "Deadbeat Jim",
  "address" : "1 E 161st St, Bronx, NY 10451",
  "risk tolerance" : "high"
} 
return insert json {"status" : "credit card declined"} into $users

但是，在本例中，返回的PUL包含对在内存中动态创建的JSON对象的更改。该对象的生存期仅为查询的评估期，因此该程序没有明显的效果

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

如果

collection

函数以某种方式映射到文档存储（如Couchbase或MongoDB）中的数据库（即，如果引擎被记录并配置为执行此操作），则以下查询将在语义上对此文档存储应用更新

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

jsoniq version "1.0";
let $users := collection("users")[$$.name eq "Jim"]
return insert json {"status" : "credit card declined"} into $users

复制修改返回表达式（在XQuery中也称为transform表达式，参见本页的其他答案）提供了一种在内存中应用更改的方法，而不会丢失更改，也不会有任何持久存储。它：

jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users

• 创建JSON对象（作为另一个对象的副本）或XML节点等
• 通过应用从修改表达式获得的PUL修改该对象（重要提示：这没有明显的副作用，因为只修改了一个副本）
• 返回修改后的副本

---

对于高级用户：在这种情况下，copy子句包含一个构建新对象的构造函数，因此优化器实际上可以跳过复制。

它说错误在第13行。这是哪一行？最后一行返回$users应该有一个

在前一行的末尾？（也可能是之前的一行。）尝试了，但得到了意想不到的语法错误“
jsoniq version "1.0";
copy $users := {
      "name" : "Deadbeat Jim",
      "address" : "1 E 161st St, Bronx, NY 10451",
      "risk tolerance" : "high"
} 
modify insert json {"status" : "credit card declined"} into $users
return $users