DESCRIBE
Syntax Forms 语法
Field Properties 字段属性
1. DESCRIBE FIELD ...
Properties of an Internal Table 内表属性
2. DESCRIBE TABLE ...
Distance Between Two Fields 两字段的间隔
3. DESCRIBE DISTANCE ...
Effect 作用
You can use the variants of the statement DESCRIBE listed above to specify some of the properties that have data objects at runtime.
你可以使用上面列出的DESCRIBE的各种变式来指出数据对象所具有的某些属性在运行时。
Notes 注
- The statement DESCRIBE is basically used to specify the properties of data objects of elementary data types. If DESCRIBE is used for structures or data objects of deeper data types like strings, internaltables, or reference variables, only elementary properties can be specified. Additional information, for example, the static or dynamic type of a reference variable cannot be determined by DESCRIBE. For this information, you must use the type classes of the Run Time Type Services (RTTS), which allow the specification all properties of data objects of all data types. Since the functions of the RTTS type classes comprise the complete functions of the DESCRIBE statement, the system classes can be used instead of the statement.
语句DESCRIBE主要被用来判断基本数据类型的数据对象的属性。如果DESCRIBE被用来指定结构或者更复杂的数据对象像字符串，内表或者引用变量，就只能指定其基本属性。附加信息，例如，静态的或者动态的引用变量DESCRIGE是判断不了它的属性的。对于这种情况，你必须使用运行时类型服务的类型类，它可以指定所有数据类型的数据对象的全部属性。因为RTTS类型类的函数是由完整的describe语句组成的函数组成的，系统类可以用来替代这些语句。
- The variant DESCRIBE LIST specifies the properties of lists in the list buffer.
变式DESCRIBE LIST 指出列表的属性在列表缓冲区。
