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shubhamy3376
May 16, 2024
Question

Query data

  • May 16, 2024
  • 11 replies
  • 0 views

Hi Everyone,

I am querying the db table through query record type. This query gives the list of db records. When I am using this in interface and using index to get the particular field, it gives this list of particular field. In case of null or single it also gives list. Can anyone please help me when it is null or single value should not give list.

    11 replies

    konduruc733182
    konduruc733182
    May 16, 2024

    Please share the code snippet of both your query rule and the interface.

    S
    shubhamy3376Author
    May 16, 2024

    Below query I am using for diffrent record types

    a!localVariables(
  local!data: a!queryRecordType(
    recordType: "recordType!HM Patient",
    fields: ri!selectionField,
    filters: a!queryLogicalExpression(
      logicalExpressions: ri!logicalExpression,
      operator: "AND",
      filters: {
        a!queryFilter(
          field: "recordType!HM Patient.fields.patientIdPk_int",
          operator: "=",
          value: ri!patientIdPk_int
        ),
        a!queryFilter(
          field: "recordType!HM Patient.fields.genderId_int",
          operator: "=",
          value: ri!genderId_int
        ),
        ri!filters
      },
      ignoreFiltersWithEmptyValues: true
    ),
    pagingInfo: a!defaultValue(
      value: ri!pagingInfo,
      default: a!pagingInfo(
        startIndex: 1,
        batchSize: 50,
        sort: {
          a!sortInfo(
            field: "recordType!HM Patient.fields.patientIdPk_int",
            ascending: false()
          )
        }
      )
    ),
    fetchTotalCount: or(ri!fetchTotalCount_bool)
  ),
  if(
    or(ri!returnDataSubset_bool),
    local!data,
    index(local!data, "data", {})
  )
)
    mikes0011
    mikes0011
    Brainy
    May 16, 2024

    let me know if my earlier reply (below) makes any sense.  it looks like this is a standard use case, though it'll depend on exactly what the context is in which you want to force the returned value to not snow up as a list.

    mikes0011
    mikes0011
    Brainy
    May 16, 2024

    Queried data (of any type, be it record type or entity) is automatically treated as a list (whether single, empty, or list) until you specify otherwise.

    A common way of forcing the output to appear as single is to use the square bracket indexing to specify the first result (which is necessary even if there's only one) - like [1] after ".data" (being the result of your query).  One issue this creates is it'll break (error) if the query actually returns empty - so instead we use index() for what it's intended for, i.e. to grab the first index (if any) and specify a default value otherwise...

    index(local!myQueryResult.data, 1, {})  (note: you should replace "{}" here with "null()" to force the output to show up as simply blank instead of an empty list, if desired)

    and, as always, to avoid confusion and increase code readability, i strongly suggest that you use property() to retrieve a specific field instead of index(), since "index" implies a position in an array, and "property" implies a particular data property.

    As Konduru mentioned already, sharing a code snippet and/or result screenshots would help us specify what you'd need to do in your particular case.

    S
    shubhamy3376Author
    May 18, 2024

    Hi mikes0011, As per above, I am not sure if .data in recordtype will be supported. .data gives error "can only be indexed using square brackets" when there is one record in output. And if indexed using square brackets then it gives error "invalid index" when output is null.

    mikes0011
    mikes0011
    Brainy
    May 18, 2024

    without seeing what exactly you're trying and what exactly your query output / error is, it's hard to say, but i'm guessing you're mixing up indexing (in terms of array position) with trying to fetch the record type property (which needs to be fetched not with a dot property but either with square brackets that contain the record property reference, or in the "property()" function where the record type property reference is passed instead of the plaintext field name).

    peter.lewis
    peter.lewis
    Employee
    May 17, 2024

    I agree with what others have said about why this happens, but in general I would suggest keeping the return type as a list if it can return a variable number of results. In some cases it can actually make it harder to manage if your return type is sometimes a list or sometimes a single item. However, if it's always a list (even if it's a list of one or zero), then it's easier to troubleshoot issues and design in a way that lists are supported.

    The case to me where it does make sense to cast it to a single item (like Mike suggested) is when you know it will always return a single item (or null). For example, if you have a query that filters by the primary key, it's guaranteed to only return a single item, so you might as well cast the type to a single item as well.

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