使用 mssql-python 调用存储过程

mssql-python 驱动没有实现 DB-API 2.0 规范中的该 callproc() 方法。调用 callproc() 会引发 NotSupportedError。相反，使用ODBC {CALL ...} 转义序列配合标准查询执行方法。

存储过程的基本执行

无参数

使用 {CALL} 转义序列来执行存储过程。本例调用 sp_databases 系统存储过程，该过程不取参数，每个数据库返回一行：

import mssql_python

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

cursor.execute("{CALL sp_databases}")

for row in cursor:
    print(row.DATABASE_NAME, row.DATABASE_SIZE)

输入参数

使用位置或命名占位符传递参数：

# Single parameter
cursor.execute(
    "{CALL dbo.uspGetManagerEmployees(?)}", (16,)
)

for row in cursor:
    print(row.FirstName, row.LastName)

输出参数

声明并检索输出参数

SQL Server 存储过程可以通过输出参数返回值。使用 Transact-SQL（T-SQL）变量捕获输出值，然后用以下 SELECT 语句检索：

cursor.execute("""
    DECLARE @total_out MONEY;
    SELECT @total_out = SUM(TotalDue)
    FROM Sales.SalesOrderHeader
    WHERE CustomerID = %(customer_id)s;
    SELECT @total_out AS TotalAmount;
""", {"customer_id": 29825})

row = cursor.fetchone()
total = row.TotalAmount
print(f"Customer total: ${total}")

多个输出参数

通过声明独立变量来捕捉多个输出值。同样的模式适用于任何具有 OUTPUT 参数的存储过程：

cursor.execute("""
    DECLARE @total_orders INT, @total_spent MONEY;
    SELECT @total_orders = COUNT(*), @total_spent = SUM(TotalDue)
    FROM Sales.SalesOrderHeader
    WHERE CustomerID = %(cust_id)s;
    SELECT @total_orders AS OrderCount, @total_spent AS TotalSpent;
""", {"cust_id": 29825})

stats = cursor.fetchone()
print(f"Orders: {stats.OrderCount}, Total spent: ${stats.TotalSpent}")

返回值

捕获存储过程返回值

执行返回结果的存储过程：

cursor.execute("EXECUTE dbo.uspGetEmployeeManagers @BusinessEntityID = %(emp_id)s", {"emp_id": 5})

rows = cursor.fetchall()
if rows:
    print(f"Found {len(rows)} managers in chain")
    for row in rows:
        print(f"  Manager: {row.FirstName} {row.LastName}")
else:
    print("No managers found")

带输出参数的返回值

cursor.execute("""
    DECLARE @return_value INT, @message NVARCHAR(500);
    SELECT @return_value = CASE WHEN COUNT(*) > 0 THEN 0 ELSE 1 END,
           @message = CASE WHEN COUNT(*) > 0 THEN N'Customer found' ELSE N'Customer not found' END
    FROM Sales.Customer WHERE CustomerID = %(cust_id)s;
    SELECT @return_value AS ReturnCode, @message AS Message;
""", {"cust_id": 29825})

result = cursor.fetchone()
print(f"Return code: {result.ReturnCode}, Message: {result.Message}")

结果集

单一结果集

执行返回单个结果集的存储过程：

cursor.execute(
    "{CALL dbo.uspGetBillOfMaterials(?, ?)}",
    (800, "2026-01-01")
)

customers = cursor.fetchall()
for row in customers:
    print(f"{row.ProductAssemblyID}: {row.ComponentDesc}")

多个结果集

某些存储过程返回多个结果集。使用 nextset() 在它们之间导航：

cursor.execute("""
    SELECT TOP 1 SalesOrderID, OrderDate, TotalDue
    FROM Sales.SalesOrderHeader WHERE CustomerID = 29825;
    SELECT TOP 3 Name, ListPrice
    FROM Production.Product WHERE ListPrice > 0
    ORDER BY ListPrice DESC;
""")

# First result set: order header
order = cursor.fetchone()
print(f"Order: {order.SalesOrderID}, Date: {order.OrderDate}")

cursor.nextset()

# Second result set: products
print("Products:")
for item in cursor:
    print(f"  {item.Name}: ${item.ListPrice}")

查看更多结果集

使用 nextset() 遍历存储过程返回的所有结果集：

cursor.execute("SELECT TOP 3 ProductID, Name FROM Production.Product; SELECT TOP 3 FirstName, LastName FROM Person.Person")

result_set_num = 1
while True:
    print(f"--- Result Set {result_set_num} ---")
    for row in cursor:
        print(row)
    
    if not cursor.nextset():
        break
    result_set_num += 1

涉及存储过程的事务

显式交易控制

在事务中封装多个存储过程调用以确保原子性：

conn.autocommit = False

try:
    cursor.execute("{CALL dbo.DebitAccount(?, ?)}", (1001, 100.00))
    
    cursor.execute("{CALL dbo.CreditAccount(?, ?)}", (1002, 100.00))
    
    conn.commit()
    print("Transfer completed")
except mssql_python.DatabaseError as e:
    conn.rollback()
    print(f"Transfer failed: {e}")

让存储过程管理事务

如果存储过程处理自己的事务：

conn.autocommit = True  # Let SP manage transactions

cursor.execute("""
    DECLARE @result INT;
    EXECUTE @result = dbo.TransferFunds 
        @FromAccount = %(from_acc)s,
        @ToAccount = %(to_acc)s,
        @Amount = %(amount)s;
    SELECT @result AS TransferResult;
""", {"from_acc": 1001, "to_acc": 1002, "amount": 100.00})

result = cursor.fetchone()
if result.TransferResult == 0:
    print("Transfer successful")

错误处理

捕捉存储过程错误

处理由存储过程或 Transact-SQL 语句引发的异常：

try:
    cursor.execute("{CALL dbo.DangerousProcedure}")
except mssql_python.ProgrammingError as e:
    # Handle SQL errors raised by RAISERROR or THROW
    print(f"Stored procedure error: {e}")
except mssql_python.DatabaseError as e:
    # Handle other database errors
    print(f"Database error: {e}")

捕获PRINT语句和信息消息

SQL ServerPRINT语句和严重级别低于 11 的RAISERROR会在执行后捕获到cursor.messages中。每个条目均为一个 (message_type, message_text) 元组。当 PRINT 在结果集之前运行时，它会先占用一个不包含任何行的结果集，因此应先读取 cursor.messages，然后调用 nextset() 以访问这些行：

cursor.execute("PRINT 'Operation complete'; SELECT 1 AS Status")

for msg_type, msg_text in cursor.messages:
    print(f"Server message: {msg_text}")

cursor.nextset()
row = cursor.fetchone()
print(f"Status: {row.Status}")

当存储过程跨多个结果集发出 PRINT 消息时，请在 execute() 之后读取 cursor.messages，并在每次调用 nextset() 后再次读取，以捕获每个结果集中的消息：

cursor.execute("""
    PRINT 'Starting first result set';
    SELECT TOP 3 ProductID, Name FROM Production.Product;
    PRINT 'Starting second result set';
    SELECT TOP 3 FirstName, LastName FROM Person.Person;
""")

all_messages = []
while True:
    all_messages.extend(cursor.messages)
    if cursor.description:
        for row in cursor:
            print(row)
    if not cursor.nextset():
        break

for _, text in all_messages:
    print(f"Server: {text}")

完整 cursor.messages API 请参见光标管理。

最佳做法

使用命名参数

命名参数更清晰，且保持顺序独立性：

# Recommended: {CALL} with positional parameters
cursor.execute(
    "{CALL dbo.uspGetBillOfMaterials(?, ?)}",
    (800, "2026-01-01")
)

# Also valid: EXECUTE with named T-SQL parameters
cursor.execute("""
    EXECUTE dbo.uspGetBillOfMaterials
        @StartProductID = ?,
        @CheckDate = ?
""", (800, "2026-01-01"))

处理可空的输出参数

从存储过程获取输出参数时，检查是否为 NULL：

cursor.execute("""
    DECLARE @optional_value NVARCHAR(100);
    SELECT @optional_value = Color FROM Production.Product WHERE ProductID = %(id)s;
    SELECT @optional_value AS OutputValue;
""", {"id": 1})

result = cursor.fetchone()
if result.OutputValue is not None:
    print(f"Value: {result.OutputValue}")
else:
    print("No value returned")

在存储过程中使用 SET NOCOUNT ON

为了提升性能和更干净的结果处理，确保你的存储过程包括：

CREATE PROCEDURE dbo.MyProcedure
AS
BEGIN
    SET NOCOUNT ON;  -- Prevents "n rows affected" messages
    -- procedure logic
END

示例：完整工作流程

这里有一个实际的例子，可以调用存储过程，检索输出值并处理错误：

import mssql_python

def get_employee_report(manager_id: int) -> dict:
    """Look up a manager's employees and compute average vacation hours."""
    conn = mssql_python.connect(connection_string)
    conn.autocommit = False
    cursor = conn.cursor()

    try:
        # Get manager info
        cursor.execute("""
            SELECT BusinessEntityID, JobTitle
            FROM HumanResources.Employee
            WHERE BusinessEntityID = %(mgr)s
        """, {"mgr": manager_id})
        mgr = cursor.fetchone()
        print(f"Manager {mgr.BusinessEntityID}: {mgr.JobTitle}")

        # Get direct reports via stored procedure
        cursor.execute("{CALL dbo.uspGetManagerEmployees(?)}", (manager_id,))
        employees = cursor.fetchall()
        print(f"Found {len(employees)} employee(s)")

        # Compute average vacation hours
        cursor.execute("""
            DECLARE @avg_hours INT;
            SELECT @avg_hours = AVG(VacationHours)
            FROM HumanResources.Employee;
            SELECT @avg_hours AS AvgVacation;
        """)
        avg = cursor.fetchone().AvgVacation
        print(f"Avg vacation hours: {avg}")

        conn.commit()
        return {"manager": mgr.JobTitle, "reports": len(employees), "avg_vacation": avg}

    except mssql_python.DatabaseError as e:
        conn.rollback()
        raise
    finally:
        cursor.close()
        conn.close()

# Usage
result = get_employee_report(manager_id=16)

使用 OUTPUT INSERTED 获取生成的键值

要从 INSERT （有无存储过程）中检索身份值，可以用 OUTPUT INSERTED 代替 SCOPE_IDENTITY()。这种方法在同一结果集中返回该值：

cursor.execute("""
    INSERT INTO Production.ProductCategory (Name)
    OUTPUT INSERTED.ProductCategoryID
    VALUES (%(name)s)
""", {"name": "Custom Parts"})

new_id = cursor.fetchval()
print(f"New category ID: {new_id}")

这种模式适用于任何带有身份列的表，且不需要存储过程。

不支持的功能

callproc（）

如果调用 cursor.callproc()，mssql-python 驱动程序会引发 NotSupportedError。使用 cursor.execute("{CALL ...}") 或 cursor.execute("EXECUTE ...") 替代，正如本文所展示的。

表值参数（TVP）

当前版本（1.11.0） mssql-python不支持表值参数。如果你需要将一组行传递给存储过程，可以使用以下替代方案：

先插入临时表，再让存储过程从中读取数据。
使用 bulkcopy() 将数据加载到暂存表中。
传递一个 JSON 字符串，然后在该过程中使用 OPENJSON 解析它。

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Last updated on 2026-07-22