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Manage Design Data for Simulink Models Programmatically

A Simulink® model can use many different data sources to contain the variables and data objects that you use to specify block parameters and signal characteristics in the model and its generated code. To manage these data sources programmatically, create a connection to the data source and use a common set of functions to manage the data.

Connect to a Data Source

Use the Simulink.data.connect function to create a Simulink.data.DataConnection object for the data source. You can create a data connection object for the base workspace, model workspace, the MAT file, or the Design Data section of a data dictionary. 

bw = Simulink.data.connect("base workspace");
mw = Simulink.data.connect("model.slx");
matFile = Simulink.data.connect("model_matFile.mat");
dd = Simulink.data.connect("model_dd.sldd");

Manage Variables in a Data Source

After you create a data connection object for your data source, you can use the object functions to manage the data.

Read and Assign Variables

To read or assign variables in the data source, use dot notation or the object functions get and set.

dd.x = 10;
set(mw,"y",20);
dd.x = dd.x + mw.y;
get(dd,"x")
ans = 

    30

You can also use the object functions get and set to read and assign multiple variables.

set(dd, ["c" "d"],{3,4});
get(dd,["c" "d"])
ans = 

1x2 cell array

    {[3]}    {[4]}

If you assign a value to a variable that does not exist in the data source, a new variable is created. If the data source is a data dictionary with referenced dictionaries, the new variable is created in the top level dictionary.

If you read a variable that does not exist in the data source, the get function returns the value <missing>.

set(mw,{'e','f'},{5,6});
get(mw,{'e','x','f'})

ans = 

1x3 cell array

    {[5]}    {[<missing>]}    {[6]}

Create Objects

To create new objects in a connected data source, use the create function. You can create:

  • Variables of type double

  • Enumerations of type Simulink.data.dictionary.EnumTypeDefinition

    Note

    You cannot create new enumeration types by using dot notation or the set function.

  • Objects from the Simulink package (for supported package members, see create)

  • Objects specified by string expressions that are valid data object constructors (for example, "fixdt(1,16,12)" or "single(10)")

For some of these objects, you can call the create function with additional name-value arguments to configure additional object attributes such as enumerations and bus elements.

List Variables

To know the contents of a connected data source, use these object functions:

  • who — List variables in the data source.

  • exist — Check if a specified variable exists in the data source.

  • show — Open the data source and display the contents in Model Explorer.

Rename Variables

To rename a specific variable or multiple variables in a connected data source, call the rename function. To successfully rename a variable in the data source, the variable name must exist and the new variable name must not exist.

dd = Simulink.data.connect("model_dd.sldd",TabComplete="Vars")
dd.ax = 3;
dd.ay = 4;
success = rename(dd, {'ax', 'ay'}, {'bx', 'by'})

1x2 logical array
    1    1

Remove Variables

Remove specific variables from a connected data source or remove all variables in the data source by calling the clear and clearAll functions.

matFile = Simulink.data.connect("model_matFile.mat");
clear(matFile,"x");
clear(matFile,["y" "z"]);
clearAll(matFile);

Manage Changes to a Data Source

When you have completed your changes to the connected data source, you can choose to save or discard those changes by calling the saveChanges function or the discardChanges function. To determine if there are changes in memory that have not yet been saved to disk, call the hasUnsavedChanges function.

Manage Data Consistency in a Data Source

A data connection can have access to multiple definitions of the same variable (for example, in a data dictionary and in a referenced dictionary). Multiple definitions of the same variable are considered consistent if the properties of the objects are identical. The object functions that manage variables in a connected data source can operate with multiple definitions as long as the definitions are consistent.

Object FunctionBehavior for Multiple Definitions
get and accessing using dot notationReturns one of the definitions or reports an error if the definitions are inconsistent
set and assignment using dot notationIf definitions exist, updates each definition
whoLists variable name once for each definition
clear(var)Removes each definition matching var
exist(var)Returns true if a variable with the name var exists
rename(var)Renames each definition
getMetadata(varName)Returns an array that contains a metadata structure for each definition

Handling Inconsistent Definitions

You can determine if a variable has inconsistent definitions by calling the isConsistent function. You can identify the inconsistencies for the variable, or all variables visible to the data connection, by calling the reportInconsistency function. This function returns a dictionary object that contains a list of variables that have multiple inconsistent definitions. Each entry in the dictionary maps one of these variables to an array of structures. The structures provide the value and metadata for each definition so that you can identify the inconsistencies. For more information on the metadata available for each type of data source, see getMetadata.

For example, to determine if there are inconsistencies in your data dictionary, first get an inconsistency report for the dictionary.

dd = Simulink.data.connect("a.sldd");
rpt = reportInconsistency(dd)
r = 

dictionary (string --> cell) with 2 entries

   "kp"         --> {1x3 struct array}
   "kb"         --> {1x2 struct array}

In this case, the report identifies two variables, kp and kb that have multiple inconsistent definitions visible to the data connection. Examine the inconsistencies for one of these variables, kb, by looking at the each of its definitions.

  1. Get the dictionary item that maps kb to an array of structures that provide the value and metadata for each definition.

    rpt_kb = rpt("kb")

    rpt_kb = 

 1x2 struct array with fields:

    value
    metadata

  2. Look at the value and metadata for each kb definition.

    rpt_kb(1).value

    ans = 

1.5
    rpt_kb(2).metadata

    dictionary (string --> cell) with 5 entries

    "DataSource"       --> {'a.sldd'}
    "Section"          --> {'Design Data'}
    "LastModified"     --> {'2023-Jun-04 02:34:37.530062'}
    "LastModifiedBy"   --> {'user'}
    "Status"           --> {'Unchanged'}

    rpt_kb(2).value

    ans = 

1.6
    rpt_kb(2).metadata

    dictionary (string --> cell) with 5 entries

    "DataSource"       --> {'ra.sldd'}
    "Section"          --> {'Design Data'}
    "LastModified"     --> {'2023-Jun-05 01:30:18.130062'}
    "LastModifiedBy"   --> {'user2'}
    "Status"           --> {'Unchanged'}

    Note that the two definitions for kb have different values.

  3. Fix each inconsistency by using one of these approaches:

    • Make the value for each definition consistent.

    • Delete all but one of the variable definitions.

    • Rename all but one of the variable definitions.

Manage Source-Specific Data Tasks

For most common data management tasks you can use the Simulink.data.connect function to create a connection to your data source, then use the common set of functions provided by the Simulink.data.DataConnection object. For data source-specific tasks, create a data source-specific object, then use the functions provided by that object to manage your data.

See Also

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