docs(config): VAR_* column names in MPE_DERIVED

Matches dc/dc: VAR_NM, VAR_ORDER, VAR_TYPE, VAR_LEN, VAR_FMT, VAR_LOGIC.

docs/derived-variables.md

@@ -19,36 +19,36 @@ Derived variables are configured per table in the [MPE_DERIVED](/tables/mpe_deri
 Each row defines one variable:
 
  - `LIBREF` / `DSN` - the target table
- - `VARIABLE_NM` - the name of the new column
- - `VARIABLE_ORDER` - evaluation order; a variable may reference one with a lower order
- - `VARIABLE_TYPE` - `C` for character, `N` for numeric
- - `VARIABLE_LENGTH` - character length, or numeric length (1-8)
- - `VARIABLE_FORMAT` - optional, eg `DATE9.` or `DOLLAR12.2`
- - `VARIABLE_LOGIC` - the SAS expression that produces the value
+ - `VAR_NM` - the name of the new column
+ - `VAR_ORDER` - evaluation order; a variable may reference one with a lower order
+ - `VAR_TYPE` - `C` for character, `N` for numeric
+ - `VAR_LEN` - character length, or numeric length (1-8)
+ - `VAR_FMT` - optional, eg `DATE9.` or `DOLLAR12.2`
+ - `VAR_LOGIC` - the SAS expression that produces the value
  - `ACTIVE` - set to 1 to apply the variable
 
 A simple example, deriving a region from a state:
 
 ```
-VARIABLE_NM      REGION
-VARIABLE_ORDER   10
-VARIABLE_TYPE    C
-VARIABLE_LENGTH  8
-VARIABLE_FORMAT  (blank)
-VARIABLE_LOGIC   ifc(STATE in ('CA','OR','WA'),'West','East')
-ACTIVE           1
+VAR_NM      REGION
+VAR_ORDER   10
+VAR_TYPE    C
+VAR_LEN     8
+VAR_FMT     (blank)
+VAR_LOGIC   ifc(STATE in ('CA','OR','WA'),'West','East')
+ACTIVE      1
 ```
 
 A later variable can build on it, provided its order is higher:
 
 ```
-VARIABLE_NM      REGION_LABEL
-VARIABLE_ORDER   20
-VARIABLE_TYPE    C
-VARIABLE_LENGTH  14
-VARIABLE_FORMAT  (blank)
-VARIABLE_LOGIC   cats(REGION,'-',STATE)
-ACTIVE           1
+VAR_NM      REGION_LABEL
+VAR_ORDER   20
+VAR_TYPE    C
+VAR_LEN     14
+VAR_FMT     (blank)
+VAR_LOGIC   cats(REGION,'-',STATE)
+ACTIVE      1
 ```
 
 For each row, Data Controller generates the following statements when the table is read:
@@ -60,7 +60,7 @@ REGION = ifc(STATE in ('CA','OR','WA'),'West','East');
 
 The label defaults to the expression itself, prefixed with `DERIVED: `, so that computed columns are obvious when labels are switched on. The expression is truncated to the maximum label length.
 
-The type and length are declared, not inferred, so a value is truncated exactly as you specify. If `VARIABLE_FORMAT` is left blank, character variables default to `$<length>.` and numeric variables to `<length>.`; a date, time or datetime format makes the column render (and filter) as a date, time or datetime, the same way a stored column does.
+The type and length are declared, not inferred, so a value is truncated exactly as you specify. If `VAR_FMT` is left blank, character variables default to `$<length>.` and numeric variables to `<length>.`; a date, time or datetime format makes the column render (and filter) as a date, time or datetime, the same way a stored column does.
 
 ## Filtering
 
@@ -70,9 +70,9 @@ Derived columns themselves are an EDIT screen feature: the VIEW screen and the d
 
 ## Rules and limits
 
- - **Expressions only.** `VARIABLE_LOGIC` must be a single SAS expression - no semicolons, macro triggers (`%`, `&`) or comments. Conditional logic is available through functions such as `ifc()`, `choosec()`, `cats()`, `catx()`, `put()`, `input()` and `intnx()`.
- - **Ordered.** Statements are generated in `VARIABLE_ORDER` sequence. An expression may reference the physical columns of the table, and any derived variable with a lower `VARIABLE_ORDER`. A reference to a variable that is not defined earlier is rejected, because SAS would otherwise return a missing value without an error. `VARIABLE_ORDER` is required, and must be a positive integer.
- - **No collisions.** `VARIABLE_NM` must not match an existing column of the target table, or one of the reserved names (`TX_FROM`, `TX_TO`, `PROCESSED_DTTM`, `VAR_TXFROM`, `VAR_TXTO`, `VAR_PROCESSED`, `_____DELETE__THIS__RECORD_____`).
+ - **Expressions only.** `VAR_LOGIC` must be a single SAS expression - no semicolons, macro triggers (`%`, `&`) or comments. Conditional logic is available through functions such as `ifc()`, `choosec()`, `cats()`, `catx()`, `put()`, `input()` and `intnx()`.
+ - **Ordered.** Statements are generated in `VAR_ORDER` sequence. An expression may reference the physical columns of the table, and any derived variable with a lower `VAR_ORDER`. A reference to a variable that is not defined earlier is rejected, because SAS would otherwise return a missing value without an error. `VAR_ORDER` is required, and must be a positive integer.
+ - **No collisions.** `VAR_NM` must not match an existing column of the target table, or one of the reserved names (`TX_FROM`, `TX_TO`, `PROCESSED_DTTM`, `VAR_TXFROM`, `VAR_TXTO`, `VAR_PROCESSED`, `_____DELETE__THIS__RECORD_____`).
  - **Read-only.** Derived columns cannot be edited in the grid, and any value submitted for them is discarded before the approval package is created.
  - **Recomputed on every read.** The value always reflects the current data and the current definition, and there is no history of previous derived values.