在mysql中更新json中key的值

我在mysql数据库中有一个类似结构的json。

{
  "tagId": "17",
  "label": "Signature",
  "name": "Signature",
  "key": "Signature",
  "placeholder": "Sign Here",
  "type": "printDigital",
  "children": [
   {
     "name": "Signature",
     "key": "Signature",
     "type": "signatureText",
     "label": "Signature",
     "placeholder": "Sign Here"
   },
   {
     "name": "SignerUUID",
     "key": "SignerUUID",
     "type": "userUuid",
     "label": "UUID",
     "placeholder": "UUID"
   }
  ]
}

我想针对下面这样的密钥签名更新子json中name字段的值

{
  "tagId": "17",
  "label": "Signature",
  "name": "Signature",
  "key": "Signature",
  "placeholder": "Sign Here",
  "type": "printDigital",
  "children": [
   {
     "name": "SignHere",
     "key": "Signature",
     "type": "signatureText",
     "label": "Signature",
     "placeholder": "Sign Here"
   },
   {
     "name": "SignerUUID",
     "key": "SignerUUID",
     "type": "userUuid",
     "label": "UUID",
     "placeholder": "UUID"
   }
  ]
}

如何有效地更新上述值?