CREATE TABLE "pager_paper_questions" (
id INTEGER PRIMARY KEY AUTOINCREMENT,
question_id TEXT NOT NULL UNIQUE,
assignment_id TEXT NOT NULL,
type TEXT NOT NULL DEFAULT 'unknown'
CHECK(type IN ('single_choice','multiple_choice','true_false','fill_blank',
'short_answer','essay','matching','calculation','other','unknown')),
content_text TEXT NOT NULL DEFAULT '',
score REAL DEFAULT 0,
difficulty REAL DEFAULT 0.50 CHECK(difficulty >= 0 AND difficulty <= 1),
correct_answer TEXT DEFAULT '',
explanation TEXT DEFAULT '',
sort_order INTEGER DEFAULT 0,
assigned_page INTEGER DEFAULT 0,
page_order INTEGER DEFAULT 0,
image_idx INTEGER DEFAULT 0,
section TEXT DEFAULT '',
options TEXT DEFAULT '[]',
major_index TEXT DEFAULT '',
extra_content TEXT DEFAULT '[]',
ref_material_id TEXT,
ref_paragraph_index INTEGER,
create_time DATETIME DEFAULT (datetime('now'))
)