Tables

categories — Expense category table; built-in categories cannot be deleted; custom categories can be added, edited, or removed
records — Expense records table; stores each user expense entry
settings — User settings table; stores passcode lock and other preferences
password_salt — Password salt table; stores the salt for each password

categories

Expense category table; built-in categories cannot be deleted; custom categories can be added, edited, or removed

Design Notes

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Categories table (source: categories API)
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@table-comment categories Expense category table; built-in categories cannot be deleted; custom categories can be added, edited, or removed

Fields

	Name	Type	Constraints	Nullable	Default	Comment
PKAI	id	INTEGER	-	NO	-	Unique category identifier; auto-increment primary key
	name	TEXT	-	NO	-	Category name; unique constraint
	icon	TEXT	-	YES	-	Category icon emoji (optional)
	is_default	INTEGER	-	NO	0	Whether built-in category (0 = custom, 1 = built-in)
	created_at	TEXT	-	NO	(strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))	Created at, ISO 8601 format

Indexes

Name	Type	Fields
-	UNIQUE	name

records

Expense records table; stores each user expense entry

Design Notes

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Expense records table (source: records API)
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@table-comment records Expense records table; stores each user expense entry

Fields

	Name	Type	Constraints	Nullable	Default	Comment
PKAI	id	INTEGER	-	NO	-	Unique record identifier; auto-increment primary key
	amount	INTEGER	-	NO	-	Amount in yuan, stored as integer hundredths of a yuan to avoid floating-point precision issues
	category_id	INTEGER	FK `→ categories(id)`	NO	-	Category ID; foreign key to categories
	created_at	TEXT	-	NO	(strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))	Created at, ISO 8601 format
	remark	TEXT	-	YES	-	Note (optional, max 200 characters)

Indexes

Name	Type	Fields
idx_records_created_at	INDEX	created_at
idx_records_category_id	INDEX	category_id

settings

User settings table; stores passcode lock and other preferences

Design Notes

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Settings table (source: settings API)
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@table-comment settings User settings table; stores passcode lock and other preferences

Fields

	Name	Type	Constraints	Nullable	Default	Comment
	value	TEXT	-	NO	-	Setting value (password-related values stored hashed)

password_salt

Password salt table; stores the salt for each password

Design Notes

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Password-related auxiliary table (optional; for password history, etc.)
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@table-comment password_salt Password salt table; stores the salt for each password

Fields

	Name	Type	Constraints	Nullable	Default	Comment
PK	id	INTEGER	CHECK `id = 1`	NO	-	Salt identifier; currently only a single password is supported
	salt	TEXT	-	NO	-	Random salt, Base64-encoded