User - defined variables can be included in package configurations and then updated when the package is deployed 用户定义的变量可以包括在包配置中，在部署包时可以更新这些变量。
The expression uses a combination of string literals , user - defined variables , and the concatenation operator 属性。该表达式使用字符串文字、用户定义的变量和串联( + )运算符的组合。
You can create as many user - defined variables as a package requires , but you cannot create additional system variables 可以创建包所需数量的用户定义变量，但不能另外创建系统变量。
User - defined variables are defined by package developers , and system variables are defined by integration services 用户定义变量由包开发人员定义，系统变量由integration services定义。
You will learn how to modify the flat file connection manager to use a user - defined variable in the next task 您将学习如何修改平面文件连接管理器，以便在下一任务中使用用户定义的变量。
For example , the expression @ a @ b compares two user - defined variables to determine whether the constrained task runs 例如，表达式@ a > @ b比较两个用户定义的变量，以确定是否运行受约束任务。
After you have added a parameter mapping by clicking add , select a system or user - defined variable from the list or click 添加了参数映射之后，请从列表中选择系统变量或用户定义变量，或单击
You will modify the connection manager that was created in lesson 1 by using a user - defined variable to populate the connection manager s 使用用户定义的变量填充在第1课中创建的连接管理器的
The variables are typically user - defined variables , although you can also use the system variables that integration services provides 尽管也可以使用integration services提供的系统变量，但变量通常是用户定义变量。
The package - level variables include the pre - defined system variables available to a package and the user - defined variables with package scope 包级变量包括可供包使用的预定义系统变量以及作用域为包的用户定义变量。
