Constants
| Definition | Creation of constant codes | Access to constants | List of standard existing constants |
1. Definition
Constants are variables that get code values when used by the supervisor and the engine layer to return error identification or a status. Some of these constants already exist in version 6, such as the values of ‘fstat’ while using database access instructions.
Version 7 implements the dictionary of constants, a new concept intended to provide explicit symbols instead of meaningless figures that are still in use.
Technically, the constants dictionary validation generates a list of global variables coded as [V]CST_xxx where xxx is the symbol that has been defined in the dictionary. The development partner can use these variables instead of existing values.
For example, codes [V]CST_AWARNING, [V]CST_AERROR, [V]CST_AOK used to describe a warning, an error, or an OK status that a function or a method may return, are easier to read than if the values were 1, 2 or 3.
Creation of constant codes
Creating constant codes is performed in the constants dictionary where the main information that must be entered are:
- The name of the constant
- An associated data type
- A value
The coding rule for naming constants are defined in the naming document.
Access to constants
After the constants are defined and the validation is performed, the constants are available on the next connection as global values in the [V] class, with the syntax [V]CST_xxx.
List of standard existing constants
The following constants have been defined for the supervisor operations.
| General context | Name of the variable | Explanation |
|---|---|---|
| Error codes used when calling operations or methods. Every error line that can be found in the AERROR class is present in the current context. | AOK | No error encountered. |
| ASUCCESS | The operation was successful, an additional message that tells the success of the operation can be returned. | |
| AINFO | No error encountered, additional information messages returned. | |
| AWARNING | Warnings are sent, but no errors are encountered. | |
| AERROR | Some errors are encountered, the function did not work as expected, error messages are returned. | |
| AFATAL | Fatal error encountered, the function did not work at all, with potential impacts on other operations. | |
| Status code of a line within a Collection (ASTALIN property). Defines the status of a line during an update transaction managed by CRUD supervisor operations. | ANEW | A new line that has been inserted. |
| ADEL | A line in which a deletion has been requested. | |
| ANEWDEL | A Line that has been inserted and in which a deletion has already been requested. | |
| AUPD | A line that has been updated. | |
| ALL | A line that has not been modified. | |
| Position code of a line within a collection. Code can be used as a parameter for insertion or deletion of lines inside a grid. | ALASTPOS | Position at the end of the grid. |
| AFIRSTPOST | Position at the first line of the grid. | |
| ANOTDEFINED | Returned message when a position in a grid is not found. | |
| Return value from a database operation such as Read, Readlock, Write, Rewrite, RewriteByKey, Delete, DeleteByKey. This return value can be found in fstat global variable. |
AOK | 0: The database operation was successful. |
| ALOCK | 1: A locking error happenend on the current line. | |
| AOUTSEARCH | 2: When read with >= or <= operator, a result was found but not with an equal value. | |
| ADUPKEY | 3: The write or update operation failed because an attempt of creation of a duplicate key was done on an index on which no duplicate keys are allowed. | |
| AOUTKEYS | 4: Attempt of reading a key value that is smaller or greater than all existing key values. | |
| ANOREC | 5: Record not read (no current record exists). | |
| ARECTICKUPD | 6: The line no longer exists with the right updtick value (concurrency error during an update operation). | |
| ARECTICKDEL | 7: The line no longer exists with the right updtick value (concurrency error during a delete operation). | |
| Logical values | ATRUE | 1 (corresponds to the result of a comparison that is true). |
| AFALSE | 0 (corresponds to the result of a comparison that is false). | |
| AYES | 2 (corresponds to the Yes value in the local menu #1). | |
| ANO | 1 (corresponds to the No value in the local menu #1) | Level of definition for parameters (corresponds to the value of the 'NIVDEF' column in parameter dictionary) | ALEVCPY | 2 (the parameter is defined at company level). |
| ALEVFCY | 3 (the parameter is defined at site level). | |
| ALEVFOLD | 1 (the parameter is defined at folder level). | |
| ALEVLEG | 5 (the parameter is defined at legislation level). | |
| ALEVUSR | 4 (the parameter is defined at user level). | Internal data types (corresponds to the values stored in local menu #30 for the 'ATYPTYP' column in data type dictionary, with the exception of the value '13' (ATYPINSTANCE) that is not defined in this local menu) | ATYPBLOB | Blbfile type (binary object). |
| ATYPCHAR | Char type (character string in UNICODE per default). | |
| ATYPCLOB | Clbfile type (character long object). | |
| ATYPDATE | Date type. | |
| ATYPDATETIME | Datetime type. | |
| ATYPDECIMAL | Decimal type. | |
| ATYPDOUBLE | Double type (floating point with double precision). | |
| ATYPFLOAT | Float type (floating point with simple precision). | |
| ATYPINSTANCE | Instance type (instance pointer). | |
| ATYPINTEGER | Integer type (long integer). | |
| ATYPSHORTINT | Shortint type (short integer). | |
| ATYPTINYINT | Tinyint type (tiny integer). | |
| ATYPUUID | UUID type. |