What is Meta Model?
Meta model is the format that allows to captured capturing detailed information about attributes of data sets that are to be processed.
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Data set Description - The module, entity, and description of the data set.
Attribute Description - Name, Description, Format, and Length. This can be captured at both the data model and BI model levels.
Attribute Security - Masking requirement and masking information.
Attribute Transforms - Transform rule that need needs to be applied at the inbound and outbound. By default, trim is applied to all categorical attributes.
Attribute Filtering - Whether the attribute should be part of the data filterring filtering process and if so what rule.
Attribute IQM - Whether the attribute should be utilized in IQM match. For more information on IQM, please refer to IQM FAQs and BAPCore documentation.
Attribute EDA - Whether the attribute should be utilized in EDA analysis.
Attribute Calendar - Whether the attribute should be utilized in calendar join operations.
Attribute Validation - Whether the attribute should be part of the data validation process and if so what rule.
Attribute Quality - Whether the attribute should be part of the data validation process and if so what rule.
What are the data types supported in meta model?
Currently, character, integer, and numeric are supported.
Should I specify data colums columns as character data type types as well?
Yes.
How do I validate meta model against the data set?
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Every time an metamodel is used for any data movement, the defintion definition of the meta model is stored in the track folder (BAPCORE/Meta/BDL/Fact/Track) along with the batch_id of the data movement process.
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Currently, that is not supported. A child entity can only belong to one parent entity. If you specify more than one parent, workloads will fail on orphan and nested records processorprocessors.
How does nesting work if I can define only one parent entity?
When processing child entity, you can pass a coleasced coalesced meta model that has all parents to that particluar particular child based on a strict parent-child relationship. For example, X is the child of Y and Z is the child of X, you can pass the coalesced meta model (both X and Y) along with entity model Z while processing the data set for Z.
How are references to parent meta model stored in entity meta model for a particular batch process?
The parent meta model is coalesced coalesces with the entity meta model. The coalesced (entity meta model and parent entity meta model) are stored in the track folder (BAPCORE/Meta/BDL/Fact/Track) along with the batch_id of the data movement process. None of the attributes of the parent entity model are changed when coalesced with the child entity model meta model. this helps in troubleshooting if all parent entity models are appropriately applied to the child entity model for nesting processes.
What should the format of entity_effective_date_time be?
Entity effective datetime DateTime should be a string else metamodel.read will fail.
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Special character issue in filter and validation rules - filter records process would fail. Error The error log will indicate a ‘special character error’. Avoid special characters while defining filter and validation rules. If you are defining meta-model in excel or CSV, export that to an R file using dput function and search for any special characters and if there are any special characters, remove those before saving the metamodel to the core data lake.
No parent is defined in meta model - If no parent information is defined in the meta model i.e parent location and parent attributes, no nested data would be created.
For integers, the default should be ‘0' and for numeric, it should be ‘0.01’. For characters, the default value should be ‘NOT AVAILABLE’
Impute method for numeric and integer should be mean and for characters, it should be DEFAULT.
meta model column names should be all lower case.
IQM metric match should be ‘YES’ only for integer and numeric columns. This should be set to YES only for integer or numerical columns that are meaningful to data analysis. For example. you would set customer_credit_score and customer_age to ‘YES’ but not postal_code (if its defined as an integer).
IQM codes should be ‘YES' for characters columns. This should be set to YES only for categorical columns that are meaningful to data analysis. For example. you would set customer_type and customer_group to ‘YES’ but not customer_name or customer_id.
Entity Name should be exactly as defined in the HDFS folder structure. The entity name is used to dynamically lookup data lake paths.
EDA Dimensions should be ‘YES’ for character columns. This should be set to YES only for categorical columns that are meaningful to data analysis. For example. you would set customer_type and customer_group to ‘YES’ but not customer_name or customer_id. as_of_date should be set to NO for eda_dimension
EDA Metrics should be ‘YES’ for integer and numeric columns. This should be set to YES only for integer or numerical columns that are meaningful to data analysis. For example. you would set customer_credit_score and customer_age to ‘YES’ but not postal_code (if its defined as an integer). as_of_date should be set to NO for eda_metric.
EDA iterate by should be the as of the date and only the as of date. This would allow for creating EDA analytics on daily basis.
entity_attribute_nested_key_role should always be set to YES when it is a parent lookup key and it is in use indicator is also set to YES
Entity Attribute Calendar Join Key should only be specified as of the date and no other key.
Each record in meta model needs to be unique (entity names, object/BI names all need to be unique).
Parent Lookup location should have a relative path instead of an absolute path (i.e. /BigAnalytixsPlatform/BAPRAM/Customer/FDL/Stage)
IQM Processor should be run with the nesting records processor ON, otherwise, turn IQM off if not Nesting.
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You can consolidate multiple Meta files into one using consolidate functionality. This is assuming that the schema of all files in the meta-model folder is the same.
Can I consolidate Meta files?
You can consolidate multiple Meta files into one using consolidate functionality. This is assuming that the schema of all files in the meta-model folder is the same.