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What Is a Data Dictionary?

A data dictionary is a persistent repository of global design data that your model uses. You can also use the base workspace to store global design data. However, a data dictionary provides more capabilities.

The dictionary only stores design data, which define parameters and signals, and include data that define the behavior of the model. The dictionary does not store simulation data, which are inputs or outputs of model simulation.

Dictionary Capabilities

Dictionary CapabilityBenefit
Dictionary as data sourceAll entries in a dictionary are persistent. You do not need to reload data during development.
Explicit data-model linkageYou can define a data dictionary as the data source for a model. During model simulation and code generation, the model retrieves design data from the data dictionary.
Change trackingWhen you modify an entry, its status is updated in the dictionary and stored as metadata that can be tracked. The dictionary also keeps track of who made the changes and when. You can also view or revert changes.
Entry comparisonCompare values of entries in two dictionaries.
Data grouping into reference dictionariesPartition and organize data items into reference dictionaries.
Model-data dependencyDiscover how entries are used in the model.
Unified interface for defining dataUse the Model Explorer to work with design data in a dictionary.
Incremental update in memoryImproved performance and scalability with minimal footprint on memory.

The following table shows a comparison of capabilities in the base workspace and a data dictionary.

CapabilityBase WorkspaceData Dictionary
Data-model linkageimplicit
Unified interface for defining data
Model-data dependency
Data entry persistence 
Data grouping 
Change tracking 
Compare and merge data entries 
Memory management 

Parts of a Dictionary

A Simulink® data dictionary is made up of two parts.

  1. Global Design Data: Contains the design data that define parameters, signals, and other data that define the behavior of the model. Data created or imported in a dictionary are stored in this part.

  2. Configurations: Contains configuration sets that determine how the model is configured during simulation. These objects control attributes such as sample time and simulation start time.

Import and Export File Formats

File FormatImport to DictionaryExport from Dictionary
MAT-file
MATLAB® script

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