Spaces:
Runtime error
Runtime error
File size: 6,501 Bytes
d60cb1f |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 |
import sqlite3
import pandas as pd
from typing import Dict, Any, Optional, List
class DatabaseHandler:
"""Handles all database operations for the Olist database."""
def __init__(self, db_path: str = "olist.sqlite"):
"""
Initialize database handler.
Args:
db_path: Path to SQLite database file
"""
self.db_path = db_path
self._verify_database()
def _verify_database(self):
"""Verify database exists and is accessible."""
try:
conn = sqlite3.connect(self.db_path)
conn.close()
except Exception as e:
raise FileNotFoundError(f"Database not found at {self.db_path}: {str(e)}")
def get_schema(self) -> str:
"""
Extract and format database schema.
Returns:
Formatted schema string with all tables and columns
"""
try:
conn = sqlite3.connect(self.db_path)
cursor = conn.cursor()
# Get all table names
cursor.execute("SELECT name FROM sqlite_master WHERE type='table';")
tables = cursor.fetchall()
schema_parts = []
for table in tables:
table_name = table[0]
# Get column information
cursor.execute(f"PRAGMA table_info({table_name});")
columns = cursor.fetchall()
# Format table schema
schema_parts.append(f"\nTable: {table_name}")
schema_parts.append("Columns:")
for col in columns:
col_name = col[1]
col_type = col[2]
is_pk = " (PRIMARY KEY)" if col[5] else ""
schema_parts.append(f" - {col_name} ({col_type}){is_pk}")
conn.close()
return "\n".join(schema_parts)
except Exception as e:
return f"Error extracting schema: {str(e)}"
def execute_query(self, sql: str, max_rows: int = 1000) -> Dict[str, Any]:
"""
Execute SQL query and return results.
Args:
sql: SQL query to execute
max_rows: Maximum number of rows to return
Returns:
Dictionary with:
- success: Boolean indicating success
- data: Pandas DataFrame with results
- row_count: Number of rows returned
- error: Error message if failed
"""
# Validate query first
if not self._validate_query(sql):
return {
"success": False,
"data": None,
"row_count": 0,
"error": "Query validation failed: Only SELECT queries are allowed"
}
try:
conn = sqlite3.connect(self.db_path)
# Execute query and fetch results
df = pd.read_sql_query(sql, conn)
# Limit rows if needed
if len(df) > max_rows:
df = df.head(max_rows)
warning = f"Results limited to {max_rows} rows"
else:
warning = None
conn.close()
return {
"success": True,
"data": df,
"row_count": len(df),
"error": None,
"warning": warning
}
except Exception as e:
return {
"success": False,
"data": None,
"row_count": 0,
"error": f"Query execution error: {str(e)}"
}
def _validate_query(self, sql: str) -> bool:
"""
Validate SQL query for safety.
Args:
sql: SQL query to validate
Returns:
True if query is safe, False otherwise
"""
sql_upper = sql.upper().strip()
# Only allow SELECT queries
if not sql_upper.startswith("SELECT"):
return False
# Block dangerous keywords
dangerous_keywords = [
"DROP", "DELETE", "INSERT", "UPDATE",
"ALTER", "CREATE", "TRUNCATE", "REPLACE"
]
for keyword in dangerous_keywords:
if keyword in sql_upper:
return False
return True
def get_table_names(self) -> List[str]:
"""
Get list of all table names in database.
Returns:
List of table names
"""
try:
conn = sqlite3.connect(self.db_path)
cursor = conn.cursor()
cursor.execute("SELECT name FROM sqlite_master WHERE type='table';")
tables = [row[0] for row in cursor.fetchall()]
conn.close()
return tables
except Exception as e:
print(f"Error getting table names: {e}")
return []
def get_table_preview(self, table_name: str, limit: int = 5) -> Optional[pd.DataFrame]:
"""
Get preview of table data.
Args:
table_name: Name of table to preview
limit: Number of rows to return
Returns:
DataFrame with sample data or None if error
"""
try:
conn = sqlite3.connect(self.db_path)
df = pd.read_sql_query(f"SELECT * FROM {table_name} LIMIT {limit};", conn)
conn.close()
return df
except Exception as e:
print(f"Error previewing table {table_name}: {e}")
return None
# Test function
if __name__ == "__main__":
# Quick test
db = DatabaseHandler("olist.sqlite")
print("=== Database Schema ===")
print(db.get_schema())
print("\n=== Table Names ===")
print(db.get_table_names())
print("\n=== Test Query ===")
result = db.execute_query("SELECT COUNT(*) as total_orders FROM orders;")
print(f"Success: {result['success']}")
if result['success']:
print(result['data'])
|