Section 5 (Production Pipelines) 31. Change Data Capture in Data Live Tables
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Questions and Answers

The Apply Changes Into operation creates a type 2 slowly changing dimension table.

False (B)

Using the Apply As Delete When condition, records can be removed from the target table.

True (A)

Records inserted into the target table will always replace existing records regardless of primary key matching.

False (B)

Once data is updated in the target table, it can still be used as a streaming source without issues.

<p>False (B)</p> Signup and view all the answers

The Except keyword is used to specify primary keys for a table.

<p>False (B)</p> Signup and view all the answers

Change Data Capture identifies and captures changes made to data in both the source and target.

<p>False (B)</p> Signup and view all the answers

New records, updated records, and deleted records are all types of changes tracked by Change Data Capture.

<p>True (A)</p> Signup and view all the answers

Metadata information logged by Change Data Capture events includes a version number or timestamp.

<p>True (A)</p> Signup and view all the answers

The Apply Changes Into command in Delta Live Tables allows changes to be applied without creating the target table first.

<p>False (B)</p> Signup and view all the answers

The Sequence By condition is used to specify which fields should be deleted from the target table.

<p>False (B)</p> Signup and view all the answers

Delta Live Tables processes CDC feeds either as data streams or in XML files.

<p>False (B)</p> Signup and view all the answers

The Apply As Delete When condition specifies records that should be updated in the target table.

<p>False (B)</p> Signup and view all the answers

Late arriving records are automatically ordered using a user-provided sequencing key in the Apply Changes Into command.

<p>True (A)</p> Signup and view all the answers

What is the default behavior of the Apply Changes Into operation for insert and update events?

<p>Upsert the CDC events into the target table. (D)</p> Signup and view all the answers

Which of the following accurately describes the Apply As Delete When condition?

<p>It defines criteria for processing delete events. (A)</p> Signup and view all the answers

What effect does creating a type 1 slowly changing dimension have on data in the target table?

<p>Overwrites original information for matching keys. (A)</p> Signup and view all the answers

What is a disadvantage of the Apply Changes Into operation in terms of streaming sources?

<p>It breaks the append-only requirements for streaming table sources. (A)</p> Signup and view all the answers

How does the Except keyword function in the context of a target table?

<p>It allows certain columns to be ignored during processing. (A)</p> Signup and view all the answers

What happens to downstream results when records arrive out of order?

<p>They need to be re-computed to reflect updates. (B)</p> Signup and view all the answers

Which option correctly states how primary keys are utilized in a target table?

<p>Primary keys can be specified to enforce unique records. (D)</p> Signup and view all the answers

What is the primary purpose of Change Data Capture (CDC)?

<p>To identify and capture changes made to data in the source system. (A)</p> Signup and view all the answers

What kind of changes does Change Data Capture track?

<p>New, updated, and deleted records. (A)</p> Signup and view all the answers

Which command is used in Delta Live Tables to apply changes from a CDC feed?

<p>Apply Changes Into (D)</p> Signup and view all the answers

What metadata is essential for tracking changes in CDC events?

<p>Operation type and timestamp. (B)</p> Signup and view all the answers

In Delta Live Tables, what does the KEYS clause specify in the Apply Changes Into command?

<p>The primary key fields for record identification. (A)</p> Signup and view all the answers

What happens to records in the target table when the Apply As Delete When condition is met?

<p>They are deleted from the target table. (C)</p> Signup and view all the answers

How does Delta Live Tables handle late arriving records in the CDC process?

<p>They are automatically ordered using a user-provided sequencing key. (D)</p> Signup and view all the answers

Which of the following statements about the target Delta Live Table is true before executing the Apply Changes Into command?

<p>It should already be created prior to executing the command. (D)</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Change Data Capture (CDC) = Tracks changes to data in source and target Type 1 Slowly Changing Dimension = Overwrites original information with updates Apply As Delete When = Condition for removing records from target table Except Keyword = Specifies columns to ignore in the target table</p> Signup and view all the answers

Match the following operations with their effects on the target table:

<p>Insert operation = Adds new records to the target table Update operation = Modifies existing records that match the key Delete operation = Removes records based on specified condition Append-only requirement = Necessary for using tables as streaming sources</p> Signup and view all the answers

Match the following scenarios with their outcomes:

<p>Records arriving out of order = Downstream results must be recomputed Using Type 2 Slowly Changing Dimension = Creates a history of all changes Applying changes with Append-only = Restricts updates and deletions No primary key specified = Multiple records can exist with the same key</p> Signup and view all the answers

Match the following terms related to Change Data Capture with their definitions:

<p>Change Data Capture = Process of identifying and capturing changes in data sources Apply Changes Into = Command used to apply changes to a target table Keys = Identification of primary key fields in the target table Sequence By = Specification of the sequence field for ordering operations</p> Signup and view all the answers

Match the types of records in Change Data Capture to their corresponding actions:

<p>Inserted records = New records to be added to the target Updated records = Records requiring reflection of changes in the target Deleted records = Records that must be removed from the target Late arriving records = Records arriving after initial processing is complete</p> Signup and view all the answers

Match the following Delta Live Tables features with their descriptions:

<p>Apply Changes Into = Applies changes from a CDC feed directly Sequence By condition = Used to order records based on a key Metadata logging = Includes version number or timestamp for tracking Primary key specification = Determines uniqueness of records in the table</p> Signup and view all the answers

Match the metadata information logged by Change Data Capture events with their descriptions:

<p>Operation field = Indicates whether a record is inserted, updated or deleted Version number = Tracks the version of the record Timestamp = Records the time at which the change occurred Record data = Holds the actual data of the changed record</p> Signup and view all the answers

Match the following terms related to CDC with their correct implications:

<p>Upsert = Inserts or updates records depending on key match Streaming source = Requires append-only behavior for data Field specification = Determines which fields are affected by operations Late arriving records = May require ordering for proper processing</p> Signup and view all the answers

Match the following key functions with their roles in data processing:

<p>Apply Changes Into command = Facilitates change application in Delta Live Tables Primary key mapping = Ensures unique identification of records Update behavior = Enables modification of existing data Ignore columns = Uses the Except keyword for specific exclusions</p> Signup and view all the answers

Match the commands or conditions in Delta Live Tables with their functions:

<p>Apply As Delete When = Specifies records to be deleted from the target table FROM clause = Identifies the CDC feed table as the streaming source KEYS clause = Determines how to match primary keys during the process Apply Changes Into command = Executes the insertion and updating operations on target</p> Signup and view all the answers

Match the following concepts with their respective characteristics:

<p>CDC feeds = Can be processed as data streams or XML Type 2 Slowly Changing Dimension = Maintains all versions of records Delete conditions = Specifies criteria for record removal Data integrity = Ensures consistency between source and target tables</p> Signup and view all the answers

Match the outcome of applying changes to the target table with the respective record type:

<p>Most recent change = What is applied for records with multiple entries Deleted records = Not found in the final target table New records = Added to the target table during the application process Updated records = Replace existing records based on primary key match</p> Signup and view all the answers

Match the types of data formats used to receive CDC feeds with their characteristics:

<p>Data streams = Continuous flow of data for immediate processing JSON files = Structured text format suitable for storing data XML files = Markup language format for data representation CDC feeds = Sources through which changes are sent to the target</p> Signup and view all the answers

Match the components of the CDC process with their roles:

<p>Event logging = Records changes in the data source Target table = Where changes from the source are applied Primary key = Unique identifier for matching records Sequencing key = Determines the order of processing changes</p> Signup and view all the answers

Match the features of the Apply Changes Into command with their descriptions:

<p>Automatic ordering = Handles late arriving records appropriately Modification detection = Updates existing records when keys match Insertion logic = Adds new records to the target if keys do not match Field specification = Lists fields to be included in the target table</p> Signup and view all the answers

Study Notes

Change Data Capture (CDC) Overview

  • Change Data Capture (CDC) identifies and captures changes made to data in the source and delivers them to the target.
  • Changes include inserting new records, updating existing records, and deleting records at the source that must be reflected in the target.
  • Changes are logged as events containing both data and metadata, which indicates the nature of changes (insert, update, delete) along with a version number or timestamp for order.

CDC Events Example

  • In a target table, the most recent change should be applied for each record.
  • Example:
    • "Canada" is to be deleted from the target.
    • "USA" and "India" are new records that need to be inserted.
  • The target will not have the deleted record (Canada).

CDC Feed and Processing

  • CDC feed can come from the source as a data stream or in formats like JSON files.
  • Delta Live Tables handle CDC processing using the Apply Changes Into command.

Apply Changes Into Command

  • Command syntax: Apply changes into <target_table> FROM <CDC_feed_table>.
  • KEYS clause identifies primary key fields, where matches in the target table dictate if a record is updated or inserted.
  • Apply As Delete When condition specifies when to delete records based on a delete operation field.
  • Sequence By allows for specifying order in which operations should be applied.
  • Target Delta Live Table must be created before executing this command.

Features of Apply Changes Into

  • Automatically orders late arriving records to ensure integrity in downstream results.
  • Handles deletes to ensure values are removed from later pipeline tables.
  • Default behavior is upsert, updating rows matching specified keys or inserting new records if no match exists.
  • Optional conditions for managing delete events.
  • Supports defining single or multiple primary keys for tables.
  • Except keyword can specify columns to ignore during processing.
  • Can create slowly changing dimension tables (Type 1 or Type 2), with Type 1 being the default, which means updates overwrite original records.

Considerations and Limitations

  • Updates and deletes in the target table break the append-only requirement for streaming sources.
  • Once a target table is updated or records are deleted, it can no longer be utilized as a streaming source in subsequent layers.

Change Data Capture (CDC) Overview

  • Change Data Capture (CDC) identifies and captures changes made to data in the source and delivers them to the target.
  • Changes include inserting new records, updating existing records, and deleting records at the source that must be reflected in the target.
  • Changes are logged as events containing both data and metadata, which indicates the nature of changes (insert, update, delete) along with a version number or timestamp for order.

CDC Events Example

  • In a target table, the most recent change should be applied for each record.
  • Example:
    • "Canada" is to be deleted from the target.
    • "USA" and "India" are new records that need to be inserted.
  • The target will not have the deleted record (Canada).

CDC Feed and Processing

  • CDC feed can come from the source as a data stream or in formats like JSON files.
  • Delta Live Tables handle CDC processing using the Apply Changes Into command.

Apply Changes Into Command

  • Command syntax: Apply changes into <target_table> FROM <CDC_feed_table>.
  • KEYS clause identifies primary key fields, where matches in the target table dictate if a record is updated or inserted.
  • Apply As Delete When condition specifies when to delete records based on a delete operation field.
  • Sequence By allows for specifying order in which operations should be applied.
  • Target Delta Live Table must be created before executing this command.

Features of Apply Changes Into

  • Automatically orders late arriving records to ensure integrity in downstream results.
  • Handles deletes to ensure values are removed from later pipeline tables.
  • Default behavior is upsert, updating rows matching specified keys or inserting new records if no match exists.
  • Optional conditions for managing delete events.
  • Supports defining single or multiple primary keys for tables.
  • Except keyword can specify columns to ignore during processing.
  • Can create slowly changing dimension tables (Type 1 or Type 2), with Type 1 being the default, which means updates overwrite original records.

Considerations and Limitations

  • Updates and deletes in the target table break the append-only requirement for streaming sources.
  • Once a target table is updated or records are deleted, it can no longer be utilized as a streaming source in subsequent layers.

Change Data Capture (CDC) Overview

  • Change Data Capture (CDC) identifies and captures changes made to data in the source and delivers them to the target.
  • Changes include inserting new records, updating existing records, and deleting records at the source that must be reflected in the target.
  • Changes are logged as events containing both data and metadata, which indicates the nature of changes (insert, update, delete) along with a version number or timestamp for order.

CDC Events Example

  • In a target table, the most recent change should be applied for each record.
  • Example:
    • "Canada" is to be deleted from the target.
    • "USA" and "India" are new records that need to be inserted.
  • The target will not have the deleted record (Canada).

CDC Feed and Processing

  • CDC feed can come from the source as a data stream or in formats like JSON files.
  • Delta Live Tables handle CDC processing using the Apply Changes Into command.

Apply Changes Into Command

  • Command syntax: Apply changes into <target_table> FROM <CDC_feed_table>.
  • KEYS clause identifies primary key fields, where matches in the target table dictate if a record is updated or inserted.
  • Apply As Delete When condition specifies when to delete records based on a delete operation field.
  • Sequence By allows for specifying order in which operations should be applied.
  • Target Delta Live Table must be created before executing this command.

Features of Apply Changes Into

  • Automatically orders late arriving records to ensure integrity in downstream results.
  • Handles deletes to ensure values are removed from later pipeline tables.
  • Default behavior is upsert, updating rows matching specified keys or inserting new records if no match exists.
  • Optional conditions for managing delete events.
  • Supports defining single or multiple primary keys for tables.
  • Except keyword can specify columns to ignore during processing.
  • Can create slowly changing dimension tables (Type 1 or Type 2), with Type 1 being the default, which means updates overwrite original records.

Considerations and Limitations

  • Updates and deletes in the target table break the append-only requirement for streaming sources.
  • Once a target table is updated or records are deleted, it can no longer be utilized as a streaming source in subsequent layers.

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Description

This quiz explores the concept of Change Data Capture (CDC) and its implementation in Data Live Tables. You will learn how CDC identifies and processes data changes, including new and updated records, from the source to the target. Gain insights into the significance of CDC in data management and processing.

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