topic Operator Assocation Issue in QlikView

Operator Assocation Issue

Mon, 26 Jan 2026 18:19:17 GMT

Hi Community,

I am new to expressor, And try to connect three operators with each other. as illustrated in attached image files.

the connection two the 3rd generating error message as

SampleDataflow1:

Read File 1:

Error: The Attribute "field1" is required by another operator downstream of this location, but this requirement has not been satisfied.

Error: The Attribute "field2" is required by another operator downstream of this location, but this requirement has not been satisfied.

Error: The Attribute "field3" is required by another operator downstream of this location, but this requirement has not been satisfied.

Error: The Attribute "field4" is required by another operator downstream of this location, but this requirement has not been satisfied.

Write File 2:

Error: The Attribute "field1" is required by this operator, but this requirement has not been satisfied.

Error: The Attribute "field2" is required by this operator, but this requirement has not been satisfied.

Error: The Attribute "field3" is required by this operator, but this requirement has not been satisfied.

Error: The Attribute "field4" is required by this operator, but this requirement has not been satisfied.

Re: Operator Assocation Issue

Sat, 08 Sep 2012 12:54:10 GMT

I am not an expert, but it seems that the schemas does not match or at least this had occured to me when a had this kind of error messages.

You should try to match the composite types of input 1 to outputs by editing the schemas.

There is an excellent example by Mike Tarallo here:

http://www.youtube.com/watch?v=C198eBIYMLQ&list=UUtLWV632L8lv2OhOrR9K4RQ&index=6&feature=plcp

Re: Operator Assocation Issue

Michael_Tarallo — Sun, 09 Sep 2012 18:42:12 GMT

Hello MOHAMMED,

(Diamantis - thanks for your contribution - the video you referenced is defintiely a great way to learn about Schemas and Semantic Types)

This is definitely an area that requires some training on the product but is also easily handled once you have a grasp on the use of Schemas and Semantic Types and how they represent data in a flow

If a schema used for writing to a target has attributes in it that are not referenced or mapped in the dataflow (or read schema) you will see that error you are mentioning.

Here are some things to remember:

Schemas are used by READ and WRITE operators only
Schemas describe the PHYSICAL EXTERNAL FIELDS of source or target data and map to a collection of LOGICAL INTERNAL ATTRIBUTES called a Semantic Type
The LEFT side of a Schema contains the external PHYSICAL FIELDS
The MIDDLE of a Schema contains the mappings
(some can be edited to translate data from one data type to another)
You use mappings to map data from the PHYSICAL FIELDS to the LOGICAL ATTRIBUTES in the Semantic Type
The RIGHT side of the Schema contains the INTERNAL LOGICAL ATTRIBUTES you can call this the Metadata
Semantyic Types are used and referenced inside of Schemas - as local or shared composite types
The COLLECTION of logical attributes are called a Compostie Semantic Type
By default when creating a schema from a physical file, table etc - it creates a local copy of the Semantic Type which is called a Local Composite Type
Semantic Type data types are generic or known as primitive
- String, Integer, Decimal, Double,DateTime,Byte
Semantic Types can be defined as "Actionable" because they contain "Active Metadata"
as you can assign constraints, default values, corrective actions and error handling all within the Type
Semantic Types can be SHARED and ASSIGNED to other Schemas to be reused
NOTE: Shared Semantic types RETAIN the rules (constraints, default values, corrective actions and error handling) defined in them - so be careful when using them in Transform and other operators as the data flowing through them migh trigger the rule and cause an error during the flow.
A Transform Operator that is used to transform existing data or create NEW attributes can also SHARE those Ouput Attributes and then have them ASSIGNed to a Schema that will be mapped to the target
Semantic Types' attribute NAMES AND DATA TYPES MUST ultimately match the target schema it is writing to
Reject Ports on READ Operators that connect to WRITE operators will have a different Schema layout (than the original read schema) and need to be created from Upstream output. Here are the attributes that are produced from the reject port.

RejectType - type of reject
RecordNumber - the number of the data record that was rejected
RecordData - a comma delimited string of the actual data values rejected encapsulated in quotes
RejectReason - the reason the data was rejected
RejectMessage - system generated additional messagesReject Ports on WRITE Operators can use the same schema that is writing to the desired target
Reject Ports on WRITE Operators can use the same Schema Layout.

Let us know if you have any questions.

Mike T