Astera Data Stack
Version 7
Version 7
  • Welcome to Astera Data Stack Documentation
  • Release Notes
    • Upgrading Astera 6 to Version 7
    • Release Notes for Astera 7.1
    • What is New in Astera 7.4
    • What’s New in Astera 7.4.1.221
    • What’s New in Astera 7.6
    • Upgrading to Astera 7.6
  • Setting Up
    • System Requirements
    • Installing Astera Data Integrator
    • Setting up Astera Integration Server 7
    • UI Walkthrough - Astera Data Integrator
  • Dataflows
    • Introducing Dataflows
    • Sources
      • Setting Up Sources
      • Raw Text Filters in File Sources
      • COBOL File Source
      • Database Table Source
      • Data Model Source
      • Delimited File Source
      • Email Source
      • Excel Workbook Source
      • File System Items Source
      • Fixed Length File Source
      • PDF Form Source
      • Report Source
      • SQL Query Source
      • XML/JSON File Source
    • Transformations
      • Aggregate Transformation
      • Apply To All Transformation
      • Constant Value Transformation
      • Data Cleanse Transformation
      • Data Quality Rules Transformation
      • Denormalize Transformation
      • Distinct Transformation
      • Expression Transformation
      • Filter Transformation
      • Function Transformations
      • Join Transformation
      • Merge Transformation
      • Normalize Transformation
      • Passthru Transformation
      • Rest Client
      • Route Transformation
      • Sequence Generator Transformation
      • Sort Transformation
      • Sources as Transformations
      • Subflow Transformation
      • Tree Join Transformation
      • Union Transformation
      • Web Service Transformation
    • Destinations
      • Setting Up Destinations
      • Database Table Destination
      • Delimited File Destination
      • Excel Workbook Destination
      • Fixed Length File Destination
      • SQL Statement Destination
      • XML/JSON File Destination
    • Data Logging and Profiling
      • Creating Data Profile
      • Creating Field Profile
      • Data Quality Mode
      • Record Level Log
      • Using Data Quality Rules in Astera
    • Database Write Strategies
      • Database Write Strategies
    • Text Processors
      • Fixed Length Parser
      • Fixed Length Serializer
  • Workflows
    • Adding Workflow Tasks
    • Creating Workflows
    • Using Workflow Designer
    • Customizing Workflows With Parameters
    • Workflows with a Dynamic Destination Path
    • Resuming and Rerunning Workflows in Astera
  • Subflows
    • Using Subflows
  • Functions
    • Functions Glossary
    • Introducing Function Transformations
    • Custom Functions
    • Logical
      • Coalesce (Any value1, Any value2)
      • IsNotNull (AnyValue)
      • IsRealNumber (AnyValue)
      • IsValidSqlDate (Date)
      • IsDate (AnyValue)
      • If (Boolean)
      • If (DateTime)
      • If (Double)
      • Exists
      • If (Int64)
      • If (String)
      • IsDate (str, strformat)
      • IsInteger (AnyValue)
      • IsNullOrWhitespace (StringValue)
      • IsNullorEmpty (StringValue)
      • IsNull (AnyValue)
      • IsNumeric (AnyValue)
    • Conversion
      • GetDateComponents (DateWithOffset)
      • ParseDate (Formats, Str)
      • GetDateComponents (Date)
      • HexToInteger (Any Value)
      • ToInteger (Any value)
      • ToDecimal (Any value)
      • ToReal (Any value)
      • ToDate (String dateStr)
      • TryParseDate (String, UnknownDate)
      • ToString (Any value)
      • ToString (DateValue)
      • ToString (Any data, String format)
    • Math
      • Abs (Double)
      • Abs (Decimal)
      • Ceiling (Real)
      • Ceiling(Decimal)
      • Floor (Decimal)
      • Floor (Real)
      • Max (Decimal)
      • Max (Date)
      • Min (Decimal)
      • Min (Date)
      • Max (Real)
      • Max (Integer)
      • Min (Real)
      • Pow (BaseExponent)
      • Min (Integer)
      • RandomReal (Int)
      • Round (Real)
      • Round (Real Integer)
      • Round (Decimal Integer)
      • Round (Decimal)
    • Financial
      • DDB
      • FV
      • IPmt
      • IPmt (FV)
      • Pmt
      • Pmt (FV)
      • PPmt
      • PPmt (FV)
      • PV (FV)
      • Rate
      • Rate (FV)
      • SLN
      • SYD
    • String
      • Center (String)
      • Chr (IntAscii)
      • Asc (String)
      • AddCDATAEnvelope
      • Concatenate (String)
      • ContainsAnyChar (String)
      • Contains (String)
      • Compact (String)
      • Find (Int64)
      • EndsWith (String)
      • FindIntStart (Int32)
      • Extract (String)
      • GetFindCount (Int64)
      • FindLast (Int64)
      • GetDigits (String)
      • GetLineFeed
      • Insert (String)
      • IsAlpha
      • GetToken
      • IndexOf
      • IsBlank
      • IsLower
      • IsUpper
      • IsSubstringOf
      • Length (String)
      • LeftOf (String)
      • Left (String)
      • IsValidName
      • Mid (String)
      • PadLeft
      • Mid (String Chars)
      • LSplit (String)
      • PadRight
      • ReplaceAllSpecialCharsWithSpace
      • RemoveChars (String str, StringCharsToRemove)
      • ReplaceLast
      • RightAlign
      • Reverse
      • Right (String)
      • RSplit (String)
      • SplitStringMultipleRecords
      • SplitStringMultipleRecords (2 Separators)
      • SplitString (3 separators)
      • SplitString
      • SplitStringMultipleRecords (3 Separators)
      • Trim
      • SubString (NoOfChars)
      • StripHtml
      • Trim (Start)
      • TrimExtraMiddleSpace
      • TrimEnd
      • PascalCaseWithSpace (String str)
      • Trim (String str)
      • ToLower(String str)
      • ToProper(String str)
      • ToUpper (String str)
      • Substring (String str, Integer startAt)
      • StartsWith (String str, String value)
      • RemoveAt (String str, Integer startAt, Integer noofChars)
      • Proper (String str)
      • Repeat (String str, Integer count)
      • ReplaceAll (String str, String lookFor, String replaceWith)
      • ReplaceFirst (String str, String lookFor, String replaceWith)
      • RightOf (String str, String lookFor)
      • RemoveChars (String str, String charsToRemove)
      • SplitString (String str, String separator1, String separator2)
    • Date Time
      • AddMinutes (DateTime)
      • AddDays (DateTimeOffset)
      • AddDays (DateTime)
      • AddHours (DateTime)
      • AddSeconds (DateTime)
      • AddMonths (DateTime)
      • AddMonths (DateTimeOffset)
      • AddMinutes (DateTimeOffset)
      • AddSeconds (DateTimeOffset)
      • AddYears (DateTimeOffset)
      • AddYears (DateTime)
      • Age (DateTime)
      • Age (DateTimeOffset)
      • CharToSeconds (Str)
      • DateDifferenceDays (DateTimeOffset)
      • DateDifferenceDays (DateTime)
      • DateDifferenceHours (DateTimeOffset)
      • DateDifferenceHours (DateTime)
      • DateDifferenceMonths (DateTimeOffset)
      • DateDifferenceMonths (DateTime)
      • DatePart (DateTimeOffset)
      • DatePart (DateTime)
      • DateDifferenceYears (DateTimeOffset)
      • DateDifferenceYears (DateTime)
      • Month (DateTime)
      • Month (DateTimeOffset)
      • Now
      • Quarter (DateTime)
      • Quarter (DateTimeOffset)
      • Second (DateTime)
      • Second (DateTimeOffset)
      • SecondsToChar (String)
      • TimeToInteger (DateTime)
      • TimeToInteger (DateTimeOffset)
      • ToDate Date (DateTime)
      • ToDate DateTime (DateTime)
      • ToDateString (DateTime)
      • ToDateTimeOffset-Date (DateTimeOffset)
      • ToDate DateTime (DateTimeOffset)
      • ToDateString (DateTimeOffset)
      • Today
      • ToLocal (DateTime)
      • ToJulianDate (DateTime)
      • ToJulianDayNumber (DateTime)
      • ToTicks (Date dateTime)
      • ToTicks (DateTimeWithOffset dateTime)
      • ToUnixEpoc (Date dateTime)
      • ToUtc (Date dateTime)
      • UnixTimeStampToDateTime (Real unixTimeStamp)
      • UtcNow ()
      • Week (Date dateTime)
      • Week (DateTimeWithOffset dateTime)
      • Year (Date dateTime)
      • Year (DateTimeWithOffset dateTime)
      • DateToJulian (Date dateTime, Integer length)
      • DateTimeOffsetUtcNow ()
      • DateTimeOffsetNow ()
      • Day (DateTimeWithOffset dateTime)
      • Day (Date dateTime)
      • DayOfWeekStr (DateTimeWithOffset dateTime)
      • DayOfWeek (DateTimeWithOffset dateTime)
      • DayOfWeek (Date dateTime)
      • DateToJulian (DateTimeWithOffset dateTime, Integer length)
      • DayOfWeekStr (Date dateTime)
      • FromJulianDate (Real julianDate)
      • DayOfYear (Date dateTime)
      • DaysInMonth(Integer year, Integer month)
      • DayOfYear (DateTimeWithOffset dateTime)
      • FromUnixEpoc
      • FromJulianDayNumber (Integer julianDayNumber)
      • FromTicksUtc(Integer ticks)
      • FromTicksLocal(Integer ticks)
      • Hour (Date dateTime)
      • Hour (DateTimeWithOffset dateTime)
      • Minute (Date dateTime)
      • JulianToDate (String julianDate)
      • Minute (DateTimeWithOffset dateTime)
      • DateToIntegerYYYYMMDD (DateTimeWithOffset dateTime)
      • DateToIntegerYYYYMMDD (Date dateTime)
    • Files
      • AppendTextToFile (String filePath, String text)
      • CopyFile (String sourceFilePath, String destFilePath, Boolean overWrite)
      • CreateDateTime (String filePath)
      • DeleteFile (String filePath)
      • DirectoryExists (String filePath)
      • FileExists (String filePath)
      • FileLength (String filePath)
      • FileLineCount (String filePath)
      • GetDirectory (String filePath)
      • GetEDIFileMetaData (String filePath)
      • GetExcelWorksheets (String excelFilePath)
      • GetFileExtension (String filePath)
      • GetFileInfo (String filePath)
      • GetFileName (String filePath)
      • GetFileNameWithoutExtension (String filePath)
      • LastUpdateDateTime (String filePath)
      • MoveFile (String filePath, String newDirectory)
      • ReadFileBytes (String filePath)
      • ReadFileFirstLine (String filePath)
      • ReadFileText (String filePath)
      • ReadFileText (String filePath, String codePage)
      • WriteBytesToFile (String filePath, ByteArray bytes)
      • WriteTextToFile (String filePath, String text)
    • Date Time With Offset
      • ToDateTimeOffsetFromDateTime (dateTime String)
      • ToUtc (DateTimeWithOffset)
      • ToDateTimeOffsetFromDateTime
      • ToDateTimeOffset (String dateTimeOffsetStr)
      • ToDateTimeFromDateTimeOffset
    • GUID
      • NewGuid
    • Encoding
      • ToBytes
      • FromBytes
      • UrlEncode
      • UrlDecode
    • Regular Expressions
      • ReplaceRegEx
      • ReplaceRegEx (Integer StartAt)
    • TimeSpan
      • Minutes
      • Hours
      • Days
      • Milliseconds
    • Matching
      • Soundex
      • DoubleMetaphone
      • RefinedSoundex
  • Report Model
    • User Guide
      • Report Model Tutorial
    • Report Model Interface
      • Field Properties
      • Pattern Properties
      • Region Properties
      • Report Browser
      • Report Options
    • Use Cases
      • Applying Pattern to Line
      • Auto-Creating Data Regions and Fields
      • Auto-Parsing
      • Creating Multi-Column Data Regions
      • Floating Patterns and Floating Fields
      • How to Work with Microsoft Word (Doc/Docx) Files in a Report Model
      • How to Work With OCR Scanned Files in a Report Model
      • How to Work With PDF Scaling Factor in a Report Model
      • Line Count
      • Pattern Count
      • Pattern is a Regular Expression
    • Exporting Options
      • Exporting a Report Model
      • Exporting Report Model to a Dataflow
    • Miscellaneous
      • Astera Report Model: Performance on Different Hardware Settings and Case Complexities
      • Microsoft Word and Rich Text Format Support
      • Importing Monarch Models
  • Project Management
    • Project Management
      • Deployment
      • Parameterization
    • Job Scheduler
      • Scheduling and Running Jobs on a Server
  • Web Services
    • Configuring Google Drive API through REST Client in Astera
    • Connecting to Eloqua using Astera REST API
    • POSTing Data Using the REST Client
    • Using the REST Client to Download a Text File
  • Metadata Management
    • Lineage and Impact Analysis
  • Connectors and Providers
    • Setting Up Oracle ODP.Net Connectivity in Astera
    • Running Microsoft Access Database Engine with Astera
    • Oracle Client Tools Setup
    • Oracle Data Load Options
  • Miscellaneous
    • Job Trace Improvements
    • SmartMatch Feature
    • Synonym Dictionary File
    • Using the Data Source Browser in Astera
  • Best Practices
    • Astera Best Practices - Dataflows
    • Cardinality Errors FAQs
    • Overview of Cardinality in Data Modeling
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On this page
  • Question 1
  • Question 2
  • Question 3
  1. Best Practices

Cardinality Errors FAQs

PreviousAstera Best Practices - DataflowsNextOverview of Cardinality in Data Modeling

Last updated 9 months ago

Question 1

"While using the Route component I received the following error: "Message: Cardinality of element paths inconsistent with other source paths". Why am I getting this error?"

If you look at the dataflow below, you have a map going from ExcelSource1 directly to DatabaseDest1. You also have a map going from the same source to a Router and then the database destination. This combination of maps will result in a cardinality error during flow verification or when you run the flow.

The reason behind the error is a possible mismatch in the number of records going out of Route1 and ExcelSource1. The Route transformation is for routing entire records, not values, and it could also route fewer records than the input set through the Rule1 path (because not all of those records will meet the criteria in Rule1). As a result, it is not possible to reconcile those few records with the records flowing directly from ExcelSource1 into the database table.

You will also run into a cardinality error when trying to do this with any Set transformation. This is because a Set transformation, which works on the entire set of data, could change the order, filter, aggregate, or otherwise change the input set, increasing or reducing the number of records compared to the input set.

For example, if you have a Filter transformation instead of a Router in the dataflow above and filtered out all but 1 record out of 10 coming from the Excel workbook. From the point of view of the destination table, how many records should it write? 1 or 10? The counts don’t match up, and this is the reason you get a cardinality error. To avoid this error, a record must flow entirely through the Set transformation (e.g. Route or Filter).

Question 2

"My source data has a complex structure. I need to extract some inner loops from the source file and save the output in a comma-separated file for processing by a downstream application. How do I do this without running into a cardinality error?"

This question is frequently asked by our users who need to extract data from hierarchical files with a complex layout, such as EDI, XML or Report documents, to name a few.

An example of such an input file is shown below. This dataflow reads an EDI source file with patient eligibility data. The source file has a very complex layout, resembling a tree with a lot of levels. There are loops at many different levels in the layout, which return a collection of records in a node. In this example, we need to extract data from two nodes, EB and DTP.

The EB node is shown with the icon in the tree. This means that it is a single instance item under its parent node, LOOP_2110C. In a single instance node, each occurrence of the LOOP_2110C loop will have no more than one EB record in it.

EB also has a child node, EB03, which is a collection. Collections are shown using icons on the tree. This means that there could be many EB03 records within each parent EB record.

The other node we are extracting data from, the DTP node, is also a collection.

So we have two collections from which we need to extract the field values. Because each of the two collections may return a different number of records compared to the other collection, we cannot combine the fields from both collections, EB1, EB2, Value, EB4, EB5, EB6, DTP1, and DTP3, in a single output file. This would create a many-to-many cardinality and as a result, a cardinality error.

To avoid the cardinality error in this scenario, we need to transform the many-to-many cardinality using a Flower transformation, for example.

Flower transformation can eliminate a many-to-many cardinality, which would normally be the case when joining two sibling collections, by reducing one of the collections to a single record using the logic defined in the Flower. In our example, the Flower object acts as a filter returning the first record from the DTP collection in each LOOP_2110C record.

Notice a scope map into the Flower object shown as a blue line connecting the LOOP_2110C loop. This tells the dataflow engine to ‘scope’ the collection at that level. Because the Flower object returns 1 record from the DTP collection for each LOOP_2110C record, this effectively creates a 1:Many relationship between DTP and EB. This relationship can be saved in the destination file by de-normalizing the dataset, which repeats the single DTP record for each EB record.

A sample dataset using this transformation is shown below.

Question 3

"I am getting this cardinality error when running the dataflow: "Message: Cardinality of element paths inconsistent with other source paths". How can I modify my dataflow to avoid the error?"

The dataflow shown below tries to achieve a similar goal to the one from Question 2. The flow aims to join the output from two sibling collections, which creates a many-to-many cardinality and an error.

To fix the cardinality error, we need to transform one of the two collections into a single instance while preserving the data that needs to be extracted. In our example, it turns out that the user only needed details of the last claim in the collection of claims.

The data from all prior claims was not needed, so it could be discarded for the purpose of reducing the collection into a single record. So we added an Aggregate transformation returning a Max(WS_NOTE_DATE), as shown in the image below. The Aggregate is scoped at the root level; this is shown on the flow diagram as a blue line connecting the WS_TF_D1 node.

The aggregate returns a record with the max disbursement date among all claims in the WS_TF_D1 record, effectively returning one record from each WS_TF_R7 collection. This creates a 1:Many relationship between WS_TF_R7 and WS_TF_R10 which avoids the cardinality error in the same way we described in Question 2.

Note: For a detailed discussion of cardinality types and best practices to avoid cardinality issues, see the article.

For more information on Cardinality and ways to address it in your dataflows, click .

Cardinality
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