PPR

PPR Code Snippets

Requirement 1: A Procedure with Parameters, Selection, and Iteration

Procedure Definition

@staticmethod
def restore(data):
    themes = {}
    for theme_data in data:
        _ = theme_data.pop('id', None)  # Remove 'id' from theme_data to avoid conflicts
        css = theme_data.get("css", None)
        theme = Theme.query.filter_by(_css=css).first()
        
        if theme:
            theme.update(theme_data)  # If the theme exists, update it
        else:
            theme = Theme(**theme_data)  # If not, create a new theme
            theme.create()
        
        themes[theme._theme] = theme  # Store the restored theme in a dictionary
    
    return themes  # Return a dictionary of updated/created themes

Explanation

This function restores theme data by either updating existing themes or creating new ones.

• Procedure Name: restore
• Return Type: A dictionary containing the restored Theme objects.
• Parameter: data (list) – A list of dictionaries, where each dictionary contains theme data.
• Sequencing: The function starts by initializing an empty dictionary, iterates over the given theme data, checks for existing themes, updates them if found, or creates new ones.
• Selection: Uses an if statement to check whether a theme already exists in the database.
• Iteration: Uses a for loop to go through each theme entry in the data list, ensuring every theme is processed.

This ensures themes are efficiently restored without duplication.

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Requirement 2: Where the Procedure Gets Called

Function Call

restored_themes = Theme.restore(theme_data_list)

Explanation

• This line calls the restore function with theme_data_list as an argument, triggering the restoration process.
• The returned restored_themes dictionary contains all updated or newly created theme objects.
• This call ensures that all themes from theme_data_list are processed correctly before being used elsewhere in the application.

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Requirement 3: Storing Data in a List

List Creation

theme_list = [theme.read() for theme in Theme.query.all()]

Explanation

This line creates a structured list of all themes in the database.

• List Initialization: The theme_list variable stores all themes in a structured format.
• Data Storage: Uses list comprehension to iterate through all Theme objects retrieved from the database and calls their read() method to store them in a list.
• Efficiency: Using list comprehension makes this process more concise and efficient compared to a traditional for loop.

This ensures themes are retrieved and formatted in a list structure for easy access.

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Requirement 4: Using Data from the List

Using the List Data

for theme in theme_list:
    print(f"Theme Name: {theme['theme']}, CSS: {theme['css']}")

Explanation

• Iteration: A for loop goes through each theme in theme_list.
• Data Retrieval: Extracts the theme name and css properties for display.
• Output: Prints each theme’s details in a readable format.

This approach ensures that all stored themes are properly displayed or processed when needed.

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Summary

1. Define a procedure (restore) to update or create themes.
2. Call that procedure (restore(theme_data_list)) to process theme data.
3. Store themes in a list (theme_list) for easy access.
4. Use the list data to iterate and display the stored themes.

This structured approach ensures themes are properly handled, avoiding duplicates while maintaining efficiency.