Tuan Tran

Language (Tool)	Syntax Example	Interprets As	Notes
Ruby (Bundler)	~> 1.2.3	>= 1.2.3 and < 1.3.0	Only patch updates allowed
	~> 1.2	>= 1.2.0 and < 2.0.0	Minor & patch updates allowed
	~> 0.2.3	>= 0.2.3 and < 0.3.0	In pre-1.0, minor is treated as breaking
Node.js (npm/yarn)	~1.2.3	>= 1.2.3 and < 1.3.0	Similar to Ruby’s ~>
	^1.2.3	>= 1.2.3 and < 2.0.0	Allows minor & patch updates (more open than ~>)
	^0.2.3	>= 0.2.3 and < 0.3.0	Special rule for 0.x versions
Python (pip)	~= 1.2.3	>= 1.2.3 and < 1.3.0	Introduced in PEP 440
PHP (Composer)	~1.2.3	>= 1.2.3 and < 1.3.0	Pessimistic constraint like Ruby
Elixir (Mix)	~> 1.2.3	>= 1.2.3 and < 1.3.0	Same semantics as Ruby
Rust (Cargo)	^1.2.3	>= 1.2.3 and < 2.0.0	Follows SemVer, major version fixed
Go (go.mod)	>= 1.2.3	No pessimistic operator	Uses minimal version selection

References

[Obsidian] Collapsing a section

tuantv.nhnd@gmail.com (Tuan Tran) — Fri, 07 Feb 2025 00:00:00 +0000

Collapsible Callout in Obsidian

In Obsidian, you can collapse a section (without collapsing all sections) using a collapsible callout.

How to Create a Collapsible Callout

Use the following markdown:

> [!NOTE]- This is a collapsible callout.
> It stays collapsed by default until the reader clicks to expand it.

Important: To make a callout collapsible, add a dash (-) after the [!type], as shown above.

Pasting Multiple Lines into a Callout

Problem

Currently, if you copy and paste multiple lines into a callout, only the first line appears inside the callout. This happens because each line inside a callout must start with > (the blockquote symbol).

Solution

Follow these steps to paste multiple lines into a callout properly:

Paste your multiple lines inside the note.
Select all the lines.
Press Command + P, then search for and select “Toggle blockquote”.

🎉 Done! Now all lines will be inside the callout.

References

Free DB hosting

tuantv.nhnd@gmail.com (Tuan Tran) — Sat, 14 Sep 2024 00:00:00 +0000

Free DB hosting: https://turso.tech/

500 Databases
9GB of total storage
1 billion row reads
Unlimited Embedded Replicas

Mysql get Optimizer Trace

tuantv.nhnd@gmail.com (Tuan Tran) — Tue, 10 Sep 2024 00:00:00 +0000

-- Step 1: Enable optimizer trace
SET optimizer_trace="enabled=on";

-- Step 2: Run the query
SELECT COUNT(\*) FROM table_name;

-- Step 3: Retrieve the optimizer trace
SELECT \* FROM information_schema.OPTIMIZER_TRACE;

-- Step 4: Disable the optimizer trace
SET optimizer_trace="enabled=off";

Translate ebooks

tuantv.nhnd@gmail.com (Tuan Tran) — Sun, 08 Sep 2024 00:00:00 +0000

Mục đích

Một số sách mới, chỉ có tiếng Anh chứ chưa được dịch sang tiếng Việt. Đọc full tiếng Anh thì sẽ nhanh oải/ đọc chậm.
Đọc song ngữ có thể giúp nâng cao vốn từ vựng.

Cách thực hiện

Sử dụng plugin trong Calibre

Video hướng dẫn: https://translator.bookfere.com/

Cách này thực hiện đơn giản, non-tech cũng có thể làm dễ dàng. Có config sử dụng Google dịch => Free

Ngoài ra, ta cũng có thể config để sử dụng ChatGPT để dịch sách. (Mất phí để lấy Token)

Sử dụng ChatGPT độc lập qua commandline tool

Cách này mình đánh giá khá cao. Tool chạy nhanh, custom config okela.

Chi phí

M có test thử bằng OpenAI, model GPT-3.5, giá cả khá ổn. Cuốn sách 500 trang giá ~1.5$. Nếu dùng model GPT-4o thì khá tốn =)) Dịch khoảng 60 trang thì đã ~5$ rồi =))

Just give it a try :D

Mysql - Calculate table size

tuantv.nhnd@gmail.com (Tuan Tran) — Fri, 30 Aug 2024 00:00:00 +0000

Calculate table size

Whenever I add a new index to my table, I carefully consider the additional storage it will require.

To assess this, I typically run a command both before and after adding the index:

SELECT table_name AS `Table`,
       ROUND(data_length / 1024 / 1024, 2) AS `Data Size (MB)`,
       ROUND(index_length / 1024 / 1024, 2) AS `Index Size (MB)`
FROM information_schema.tables
WHERE table_schema = 'your_data_base_name'
  AND table_name = 'your_table_name';


+----------+----------------+-----------------+
| Table    | Data Size (MB) | Index Size (MB) |
+----------+----------------+-----------------+
| t_name   |       18922.00 |          571.36 |
+----------+----------------+-----------------+

Calculate entire database size

SELECT table_schema AS `Database`,
       ROUND(SUM(data_length) / 1024 / 1024, 2) AS `Total Data Size (MB)`,
       ROUND(SUM(index_length) / 1024 / 1024, 2) AS `Total Index Size (MB)`,
       ROUND((SUM(data_length) + SUM(index_length)) / 1024 / 1024, 2) AS `Total Size (MB)`
FROM information_schema.tables
WHERE table_schema = 'trill_sun_stg_2'
GROUP BY table_schema;

+-----------------+----------------------+-----------------------+-----------------+
| Database        | Total Data Size (MB) | Total Index Size (MB) | Total Size (MB) |
+-----------------+----------------------+-----------------------+-----------------+
| db_name         |             38236.00 |               3331.73 |        41567.73 |
+-----------------+----------------------+-----------------------+-----------------+
1 row in set (0.03 sec)

Use VIA app for keymap

tuantv.nhnd@gmail.com (Tuan Tran) — Wed, 21 Aug 2024 00:00:00 +0000

Use VIA for keymap

Setup Instructions

Connect Your Device: Use the provided USB cable to connect your device to the keyboard, ensuring the keyboard is in wired mode. Then, open the VIA online configurator in Chrome by visiting usevia.app.
Download the JSON File: Download the appropriate JSON file for your keyboard (e.g., from NuPhy’s website if you’re using a NuPhy keyboard). Upload this file manually to the VIA configurator.
Enable Design Tab: Click on the ‘SETTINGS’ tab (represented by a gear icon). Turn on the ‘Show Design Tab’ switch. This will make the design tab icon (a brush) appear in the top row of icons.
Upload JSON File: Go to the design tab, and drag the JSON file you downloaded in Step 2 into the upload area at the top. After uploading, return to the ‘CONFIGURE’ tab, click ‘Authorize Device,’ and select your device name from the pop-up window. If successful, an on-screen keyboard will appear.

Remapping a Key

Access the ‘CONFIGURE’ Tab: Go to the ‘CONFIGURE’ tab.
Remap the Key: Click on the key you want to reassign on the keyboard. Then, choose the new key value from the table. If successful, the key’s legend will update to reflect the new assignment.
Save Your Keymaps: Use the ‘SAVE+LOAD’ option (the disk icon on the left) to back up your keymaps.

References

VIA Usage Guide for NuPhy Keyboards

Fix blur text on Kindle

tuantv.nhnd@gmail.com (Tuan Tran) — Sun, 18 Aug 2024 00:00:00 +0000

Fixing Blurry Text on Kindle

When sending an ebook from Calibre to your Kindle, you might sometimes notice that the text appears blurry. To resolve this issue, follow these steps:

Open Calibre and select the ebook in question.
Click on “Convert books.”
In the conversion settings, choose “Look and Feel” from the sidebar.
Navigate to the “Styling” tab.
Under the section “Select what style information you want completely removed,” check the box for “Colors.”
Press “OK” to apply the changes, then resend the ebook to your Kindle.

Singleton class/method in Ruby

tuantv.nhnd@gmail.com (Tuan Tran) — Mon, 22 Jul 2024 00:00:00 +0000

Singleton

Allow define methods that are only available on a single object rather than all instances of a class.

Singleton Class

class MyClass
end

obj = MyClass.new

# Define a method only for this object
class << obj
  def singleton_method
    p "Singleton Method"
  end
end

obj.singleton_method
p "-" * 30

# This will raise error because the singleton method is defined only for obj
another_obj = MyClass.new
another_obj.singleton_method

class << obj opens the Singleton class of obj. Methods in this class are only available on obj and not on other instances of MyClass

Singleton Methods

class MyClass
end

obj = MyClass.new

# Define a method only for this specific object
def obj.singleton_method
  "I am a singleton method"
end

puts obj.singleton_method  # Output: "I am a singleton method"

# This will raise an error because other instances do not have this method
another_obj = MyClass.new
# puts another_obj.singleton_method

Conclusion

Singleton Class: A class created by Ruby for each object, allowing methods to be defined only on that object.
Singleton Method: A method defined for a single object, making it unique to that object.