英文:
How to declare a ValueBuilder object to be a StringSet when doing an UpdateItem in Dynamodb using gosdk?
问题
注意：我将为你翻译以下内容：
注意：这可能看起来像是这个问题的重复，但它不同之处在于我需要在golang中执行此操作，而那个问题是使用JS。
我想在goSDK中对dynamodb项执行以下操作：
UpdateExpression: 'ADD socialAccounts :socialAccountId',ExpressionAttributeValues: {':socialAccountId': {'SS': [socialAccountId]}},
通常在GoSDK中的操作如下：
expression.Add(expression.Name("socialAccounts"), expression.Value([]string{"socialAccountId"}))
然而，SDK将字符串数组作为L(List)类型而不是SS(StringSet)类型处理。
记录的错误：
Error: ValidationException: Invalid UpdateExpression: Incorrect operand type for operator or function; operator: ADD, operand type: LIST, typeSet: ALLOWED_FOR_ADD_OPERAND
我无法在文档中找到任何指定类型的功能。
有人可以帮忙吗？
为什么我要这样做：
- 即使属性
socialAccounts不存在，我也希望它能正常工作。 - 我不想使用带有
list_append的SET操作，因为那样可能会引入重复元素。
英文:
NOTE: Might seem like a duplicate of this but it's different because I need to do this via golang while that is in JS.
I want to do the following operation in goSDK on a dynamodb item:
UpdateExpression: 'ADD socialAccounts :socialAccountId',ExpressionAttributeValues: {':socialAccountId': {'SS': [socialAccountId]}},
Typically how that works out in GoSDK is:
expression.Add(expression.Name("socialAccounts"), expression.Value([]string{"socialAccountId"}))
However the SDK is not taking the array of strings as a SS(StringSet) type, but instead as a L(List) type.
Logged Error:
Error: ValidationException: Invalid UpdateExpression: Incorrect operand type for operator or function; operator: ADD, operand type: LIST, typeSet: ALLOWED_FOR_ADD_OPERAND
I'm unable to find any functionality in the docs that specify how to mention a type.
Can anyone help?
Why I want to do it this way:
- I want this to work even when the attribute
socialAccountsdoes not exist. - I don't want to use the
SETopearation withlist_appendbecause that can introduce duplicate elements.
答案1
得分: 1
如果需要指定类型，请使用dynamodb.AttributeValue：
package mainimport ("fmt""github.com/aws/aws-sdk-go/aws""github.com/aws/aws-sdk-go/service/dynamodb""github.com/aws/aws-sdk-go/service/dynamodb/expression")func main() {val := (&dynamodb.AttributeValue{}).SetSS(aws.StringSlice([]string{"socialAccountId"}))expression.Add(expression.Name("socialAccounts"), expression.Value(val))fmt.Printf("%s\n", val)}
输出结果：
{"SS": ["socialAccountId"]}
英文:
Use dynamodb.AttributeValue if you need to specify the type:
package mainimport ("fmt""github.com/aws/aws-sdk-go/aws""github.com/aws/aws-sdk-go/service/dynamodb""github.com/aws/aws-sdk-go/service/dynamodb/expression")func main() {val := (&dynamodb.AttributeValue{}).SetSS(aws.StringSlice([]string{"socialAccountId"}))expression.Add(expression.Name("socialAccounts"), expression.Value(val))fmt.Printf("%s\n", val)}
Output:
{SS: ["socialAccountId"]}
答案2
得分: 0
我更喜欢@Zeke Lu的答案而不是我的答案。
但以下是一个"不得已而为之"的方法，应该可以完成所有任务。
updateExpr := "ADD #SOCIAL :SOCIAL"expName := map[string]*string{"#SOCIAL": aws.String(SOCIAL)}expVal := map[string]*dynamodb.AttributeValue{":SOCIAL": {SS: aws.StringSlice(socialAccounts)}}_, errUpdate = tablesConnection.UpdateItem(&dynamodb.UpdateItemInput{ExpressionAttributeNames: expName,ExpressionAttributeValues: expVal,Key: key,TableName: aws.String(tableName),UpdateExpression: aws.String(updateExpr),})
英文:
I prefer @Zeke Lu 's answer over my own.
But the following is a "push-comes-to-shove" method that should accomplish everything.
updateExpr := "ADD #SOCIAL :SOCIAL"expName := map[string]*string{"#SOCIAL": aws.String(SOCIAL)}expVal := map[string]*dynamodb.AttributeValue{":SOCIAL": {SS: aws.StringSlice(socialAccounts)}}_, errUpdate = tablesConnection.UpdateItem(&dynamodb.UpdateItemInput{ExpressionAttributeNames: expName,ExpressionAttributeValues: expVal,Key: key,TableName: aws.String(tableName),UpdateExpression: aws.String(updateExpr),})
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