Event schema design in Microservices - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a table for storing event data with an event ID as the primary key.

Microservices

CREATE TABLE events (event_id [1] PRIMARY KEY, event_name VARCHAR(100));

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AINT

BVARCHAR(50)

CDATE

DTEXT

Attempts:

3 left

💡 Hint

Common Mistakes

Using VARCHAR for event_id which is less efficient for keys.

Using DATE type which is not suitable for IDs.

The event_id should be an integer type to uniquely identify each event and serve as the primary key.

2fill in blank

medium

Complete the code to add a timestamp column to record when the event occurred.

Microservices

ALTER TABLE events ADD COLUMN event_time [1];

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ATIMESTAMP

BINT

CVARCHAR(50)

DBOOLEAN

Attempts:

3 left

💡 Hint

Common Mistakes

Using INT which cannot store date/time.

Using BOOLEAN which is only true/false.

The TIMESTAMP type stores date and time information, perfect for recording event occurrence time.

3fill in blank

hard

Fix the error in the event schema by choosing the correct data type for event payload storage.

Microservices

CREATE TABLE event_payloads (payload_id INT PRIMARY KEY, event_id INT, payload [1]);

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AINT

BTEXT

CVARCHAR(255)

DBOOLEAN

Attempts:

3 left

💡 Hint

Common Mistakes

Using VARCHAR(255) which may be too short for large payloads.

Using INT or BOOLEAN which cannot store text.

Event payloads can be large JSON or text data, so TEXT type is suitable for flexible storage.

4fill in blank

hard

Fill both blanks to create a foreign key relationship between event_payloads and events tables.

Microservices

ALTER TABLE event_payloads ADD CONSTRAINT fk_event FOREIGN KEY ([1]) REFERENCES [2](event_id);

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Aevent_id

Bevents

Cpayload_id

Devent_payloads

Attempts:

3 left

💡 Hint

Common Mistakes

Using payload_id as foreign key which is incorrect.

Referencing the wrong table.

The foreign key column is event_id in event_payloads, referencing event_id in events table.

5fill in blank

hard

Fill all three blanks to create an index on event_time and event_name for faster queries.

Microservices

CREATE INDEX idx_[1] ON events ([2], [3]);

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Atime_name

Bevent_time

Cevent_name

Devent_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using event_id in the index which is already primary key.

Choosing a non-descriptive index name.

The index name is arbitrary but descriptive. Indexing event_time and event_name speeds up queries filtering or sorting by these columns.