Progress4GL：能否通过变量/参数值命名临时表字段？

Hey Joseph, great question! You're right that the static DEFINE TEMP-TABLE syntax won't let you use a variable's value for a field name directly—Progress resolves those definitions at compile time, so runtime variables can't be referenced there. But luckily, Progress4GL supports dynamic temp-table creation using handles, which lets you define fields with runtime-generated names exactly like you want.

Step-by-Step Working Solution #

Here's a practical example that achieves your goal:

DEFINE VARIABLE randomvariable AS CHARACTER INITIAL "fieldname" NO-UNDO.
DEFINE VARIABLE hTempTable    AS HANDLE NO-UNDO.
DEFINE VARIABLE hRecord       AS HANDLE NO-UNDO.

/* 1. Create a dynamic temp-table handle */
CREATE TEMP-TABLE hTempTable.

/* 2. Add your field using the variable's value as the field name */
/* Syntax: ADD-FIELD(field-name, data-type, format, label, extent) */
hTempTable:ADD-FIELD(randomvariable, "CHARACTER", "", "", ?).

/* Optional: Set extra field properties (e.g., 20-character format, custom label) */
/* hTempTable:ADD-FIELD(randomvariable, "CHARACTER", "20", "My Dynamic Field", ?) */

/* 3. Prepare the temp-table to make it usable like a static temp-table */
hTempTable:TEMP-TABLE-PREPARE("tt_table").

/* 4. Interact with the temp-table just like you would a static one */
CREATE hRecord.
hRecord:BUFFER-FIELD(randomvariable):VALUE = "Hello from a dynamic field!".

/* Test the value to confirm it works */
DISPLAY hRecord:BUFFER-FIELD(randomvariable):VALUE.

/* Clean up handles to avoid memory leaks in long-running sessions */
DELETE OBJECT hRecord.
DELETE OBJECT hTempTable.

Key Details to Keep in Mind #

• Dynamic vs Static: Static DEFINE TEMP-TABLE is processed at compile time, so it can't use runtime variables. Dynamic temp-tables use handles to build the structure on the fly, which gives you the flexibility to define fields with dynamic names.
• Handle Management: Always delete handles when you're finished with them—this prevents memory leaks that can cause issues in persistent sessions.
• Compile-Time Alternative: If your field name is known before runtime, you can use a preprocessor macro instead (but this won't work for dynamic runtime values):

  &GLOBAL-DEFINE FIELD_NAME "fieldname"
  DEFINE TEMP-TABLE tt_table field {&FIELD_NAME} AS CHARACTER.
  

内容的提问来源于stack exchange，提问作者Joseph Betts