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Sqlite Get Filesize

5 min read Oct 01, 2024
Sqlite Get Filesize

How to Get File Size in SQLite Database?

SQLite is a powerful and lightweight database engine widely used in various applications. While it's primarily known for managing structured data, you might encounter situations where you need to store file content directly within the database. This begs the question: how can you retrieve the file size stored in a SQLite database?

The answer is, unfortunately, SQLite doesn't offer a built-in function to calculate file size directly from the database. This means you need to rely on other methods to achieve this. Let's explore some approaches:

1. Using LENGTH() Function:

The LENGTH() function in SQLite can be used to determine the length of a string. This approach works when you store the file contents as a BLOB (Binary Large Object) within your database.

SELECT LENGTH(file_content) AS file_size FROM your_table WHERE file_name = 'your_file.txt';

This query retrieves the file size as the number of bytes stored in the file_content column for the file named your_file.txt.

Important Considerations:

  • This method retrieves the size of the file content as stored in the database, not the actual file size on the file system.
  • The LENGTH() function returns the number of bytes, which might differ from file size units like KB or MB.

2. External Scripting:

If you're using a programming language like Python or Node.js with SQLite, you can retrieve the file content from the database and then use built-in functions to calculate the file size.

Python Example:

import sqlite3

conn = sqlite3.connect('your_database.db')
cursor = conn.cursor()

cursor.execute("SELECT file_content FROM your_table WHERE file_name = 'your_file.txt'")
file_content = cursor.fetchone()[0]

file_size = len(file_content)

print("File Size:", file_size)

This code retrieves the file content from the database, calculates the size using len(file_content), and then prints the result.

3. File System Access:

For specific use cases, you might need to access the file system directly to determine the file size. However, this approach is not ideal for applications where you want to manage files exclusively through the SQLite database.

4. Using Blob Data Type:

SQLite uses the BLOB data type to store binary data like file contents. This type allows you to efficiently store and retrieve file content within your database.

Example:

CREATE TABLE files (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    file_name TEXT,
    file_content BLOB
);

INSERT INTO files (file_name, file_content) VALUES ('your_file.txt', ?);  -- Insert file content as BLOB

Note: The placeholder ? represents the actual file content in binary format.

5. Custom Functions in SQLite:

SQLite allows you to create custom functions. While you can't directly calculate file size within SQLite, you can create a custom function that retrieves the file content and calculates its size. This approach requires familiarity with SQLite's custom function creation process.

Conclusion:

While SQLite does not provide a direct method to get file size, you can achieve this through workarounds like using the LENGTH() function, external scripting, file system access, and custom functions. Choose the approach that best suits your specific needs and application context. Remember, it's essential to weigh the trade-offs and complexities of each method before implementation.

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