使用 mssql-python 執行查詢

mssql-python 驅動程式提供用於 SQL 查詢執行、參數化查詢、批次操作及預備語句的游標方法。

基本查詢執行程序

使用游標 execute() 方法來執行 SQL 語句:

import mssql_python

conn = mssql_python.connect(connection_string)
cursor = conn.cursor()

cursor.execute("SELECT Name, ListPrice FROM Production.Product WHERE Color = 'Black'")
rows = cursor.fetchall()

for row in rows:
    print(row.Name, row.ListPrice)

cursor.close()
conn.close()

參數化查詢

務必使用參數化查詢以防止 SQL 注入。 驅動程式的預設參數樣式為 pyformat (命名佔位符),但它也支援 qmark (位置佔位符)。 使用 qmark 來表示 ODBC {CALL} 逸出序列。

Pyformat 風格(預設)

使用帶有 %(name)s 語法的命名佔位符並傳遞字典:

cursor.execute(
    "SELECT Name, ListPrice FROM Production.Product WHERE Color = %(color)s AND ListPrice > %(price)s",
    {"color": "Black", "price": 10.00}
)

Qmark 風格

使用含有 ? 的位置佔位符,並傳入元組或清單:

cursor.execute(
    "SELECT Name, ListPrice FROM Production.Product WHERE ProductSubcategoryID = ? AND ListPrice > ?",
    (1, 10.00)
)

驅動程式會根據你的 SQL 查詢和參數類型自動偵測參數樣式。

INSERT、UPDATE、DELETE作業

對於資料修改語句,請使用參數化查詢並提交交易:

cursor.execute("CREATE TABLE #ExecDemo (Name NVARCHAR(50), CategoryID INT, Price DECIMAL(10,2))")
cursor.execute(
    "INSERT INTO #ExecDemo (Name, CategoryID, Price) VALUES (%(name)s, %(category)s, %(price)s)",
    {"name": "New Product", "category": 1, "price": 19.99}
)
conn.commit()

print(f"Rows affected: {cursor.rowcount}")

使用 executemany() 進行批次執行

executemany() 來有效率地插入多列。 驅動程式使用逐欄參數綁定以提升高效能:

products = [
    {"name": "Product A", "category": 1, "price": 10.00},
    {"name": "Product B", "category": 1, "price": 15.00},
    {"name": "Product C", "category": 2, "price": 20.00},
]

cursor.execute("CREATE TABLE #BatchDemo (Name NVARCHAR(50), CategoryID INT, Price DECIMAL(10,2))")
cursor.executemany(
    "INSERT INTO #BatchDemo (Name, CategoryID, Price) VALUES (%(name)s, %(category)s, %(price)s)",
    products
)
conn.commit()

print(f"Rows inserted: {cursor.rowcount}")

採用 qmark 樣式:

products = [
    ("Product A", 1, 10.00),
    ("Product B", 1, 15.00),
    ("Product C", 2, 20.00),
]

cursor.execute("CREATE TABLE #QmarkDemo (Name NVARCHAR(50), CategoryID INT, Price DECIMAL(10,2))")
cursor.executemany(
    "INSERT INTO #QmarkDemo (Name, CategoryID, Price) VALUES (?, ?, ?)",
    products
)
conn.commit()

多語句批次執行

在連線上使用 batch_execute() ,在單一呼叫中執行多個不同的語句:

results, cursor = conn.batch_execute(
    [
        "CREATE TABLE #BatchExec (Name NVARCHAR(50), CategoryID INT)",
        "INSERT INTO #BatchExec (Name, CategoryID) VALUES (%(name)s, %(cat)s)",
        "SELECT COUNT(*) FROM #BatchExec"
    ],
    [
        None,                                 # No params for CREATE
        {"name": "New Item", "cat": 1},       # Params for INSERT
        None                                  # No params for SELECT
    ]
)

print(f"CREATE result: {results[0]}")
print(f"INSERT affected: {results[1]} rows")
print(f"Row count: {results[2][0][0]}")

備妥語句

驅動程式預設會準備查詢(use_prepare=True)。 當你在同一游標上多次執行同一個 SQL 字串時,驅動程式會在後續呼叫時自動重用已準備好的語句:

# First execution prepares the statement
cursor.execute(
    "SELECT Name, ListPrice FROM Production.Product WHERE ProductSubcategoryID = %(subcategory_id)s",
    {"subcategory_id": 1},
)
rows1 = cursor.fetchall()

# Same SQL string on same cursor → driver reuses the prepared plan
cursor.execute(
    "SELECT Name, ListPrice FROM Production.Product WHERE ProductSubcategoryID = %(subcategory_id)s",
    {"subcategory_id": 2},
)
rows2 = cursor.fetchall()

若要跳過準備程序,改為直接執行:

cursor.execute(
    "SELECT Name, ListPrice FROM Production.Product WHERE ProductSubcategoryID = 1",
    use_prepare=False  # Uses SQLExecDirectW instead of SQLPrepareW
)

連線層級執行

對於簡單的一次性查詢,直接在連線上使用 execute()

# Creates cursor, executes, and returns cursor
cursor = conn.execute("SELECT TOP 10 Name, ListPrice FROM Production.Product")
rows = cursor.fetchall()
cursor.close()

預存程序

使用 EXECUTE 或 ODBC {CALL} 逸出語法來呼叫儲存程序。 關於輸出參數、多重結果集及交易模式的資訊,請參見 儲存程序

cursor.execute(
    "EXECUTE dbo.uspGetManagerEmployees @BusinessEntityID = %(business_entity_id)s",
    {"business_entity_id": 16}
)
rows = cursor.fetchall()

設定輸入大小

可明確 setinputsizes() 宣告參數型別,這能提升批次操作的效能:

cursor.setinputsizes([
    (mssql_python.SQL_WVARCHAR, 50, 0),   # NVARCHAR(50)
    (mssql_python.SQL_INTEGER, 0, 0),     # INT
])

cursor.executemany(
    "SELECT ProductID, Name FROM Production.Product WHERE Name LIKE ? AND ProductSubcategoryID = ?",
    [("Road%", 2), ("Mountain%", 1)]
)

Note

並非所有 SQL 型別常數都可搭配 setinputsizes() 使用。 SQL_WVARCHARSQL_INTEGER 都很可靠。 對於十進位值,請使用驅動程式的自動型別推論,而非 SQL_DECIMAL,後者有已知問題(GitHub #503)。

錯誤處理

將資料庫操作包裝成 try-except 區塊:

try:
    cursor.execute("CREATE TABLE #ErrDemo (Name NVARCHAR(50) NOT NULL)")
    cursor.execute("INSERT INTO #ErrDemo (Name) VALUES (%(name)s)", {"name": None})
    conn.commit()
except mssql_python.IntegrityError as e:
    print(f"Constraint violation: {e}")
    conn.rollback()
except mssql_python.ProgrammingError as e:
    print(f"SQL error: {e}")
    conn.rollback()

最佳做法

  1. 務必使用參數化查詢 以防止 SQL 注入。
  2. 進行大量插入時,請使用 大量複製,而非多次 execute() 呼叫。
  3. 關閉自動提交時,請明確提交交易
  4. 關閉游標和連線以便釋放資源。
  5. 使用上下文管理器 進行自動資源清理:
with mssql_python.connect(connection_string) as conn:
    with conn.cursor() as cursor:
        cursor.execute("SELECT TOP 5 Name, ListPrice FROM Production.Product")
        rows = cursor.fetchall()
# Connection and cursor automatically closed