When naming or renaming an item in ClearSCADA, you need to take into account these restrictions:
- You can include any alphanumeric character within a name.
- You can include most non-alphanumeric Unicode symbols, such as
! * ( ) - , ~ `, in a name, with the exception of the following symbols, which cannot be included as they are reserved characters:< > # % “ ; : ? . @ & = + $ { } | ^ [ ]
ATTENTION: If a database item's name includes parentheses ( ), you should ensure that each opening parenthesis is paired with a closing parenthesis. If this is not the case, any Logic programs that reference the database item will not compile successfully. For example, a point named "Analog Point (4" or "Analog Point (4))" will generate a compile error message. Multiple sets of parentheses will compile successfully, including nested parentheses. For example, a Logic program can refer to a point named "Analog Point (4)" or "Analog Point (4(x))". For more information, see Limitation for Database Item Names Referenced in Logic Programs in the ClearSCADA Guide to Logic.
- In addition to the individual characters the prefix 'WH_' is reserved for Wonderware Historian metadata field names.
- Although we do not recommend its use in database names (see below), the underscore character ( _ ) is also a legal character.NOTICE
UNEXPECTED BEHAVIOR OF APPLICATION
Avoid using the underscore character ( _ ) in names of database items. The underscore character is treated as a 'wildcard' for a single character in SQL unless it is escaped in the query. If queries are run on database item Names or FullNames on large systems in which names contain underscore characters (and the underscore characters are not escaped in the query), this could significantly impact on CPU usage while the query runs.Failure to follow these instructions can result in a significant impact on CPU usage when running SQL queries on large systems.NOTE: To avoid impacting on CPU usage during SQL queries, we recommend using the tilde ( ~ ) or hyphen ( - ) instead of the underscore character ( _ ) in names in which a non-alphanumeric character is required.
- If you rename an item in a Template, that name will be replicated in each of the Instances of that Template. (You cannot rename an item in a Group Instance directly, you can only rename the Instance Group.)
- The maximum length of a name is 63 characters. The overall full name of an item (as displayed in Queries Lists, and on the top banner of Forms, and so on) must not exceed 254 characters in total. This length includes the separation dots within the path name, and any blank spaces used within any part of the name.
Example:
An internal point is renamed Test Int Analog. The name uses 15 characters, including spaces.
The full name of the point, which is stored within the Northern Site Group in the database, is:
Northern Site.Internal Points.Test Int Analog
The full name of the point therefore uses 45 characters, including spaces and separation dots. - Each item has to have a unique name within its Group—ClearSCADA generates a diagnostic message if there is an attempt to give an item a name that already exists within that Group.
With the exception of user names (see below), you can configure items in one group to use the same name as those in another group, as long as the path is unique for each of those items. (As the path includes the Group name, this allows ClearSCADA to differentiate between similarly named items in other groups.)
Example:
The group Engine 1 has a digital point Motor 1.
The group Engine 2 also has a digital point Motor 1.
Because the full path for each digital point includes the Group name (Engine 1, or Engine 2), the full name for each digital point is unique (Engine 1.Points.Motor 1, and Engine 2.Points.Motor 1).
- Each user name has to be unique across the entire system (not just within the Group in which it is located).
Example:
Two engineers have the name John Jackson. To differentiate between their user names on the system, their initials are also used, resulting in two unique user names, John A Jackson, and John R Jackson.
Further Information
For examples that demonstrate using an ESCAPE clause in SQL queries, see the topic 'Conditions.bool-primary-like' in the SQL Technical Reference online Help. (For information about accessing the SQL Technical Reference online Help, see Display ClearSCADA Help in the ClearSCADA Guide to Using Help.)