Entity names

Explore how to use entity names in your APL query.

APl entities (datasets, tables, columns, and operators) are named.

For example, two fields or columns in the same dataset can have the same name if the casing is different and a table and a dataset may have the same name because they are not in the same scope.

Columns

• Column names are case-sensitive for resolving purposes and they have a specific position in the dataset’s collection of columns.
• Column names are unique within a dataset and table.
• In queries, columns are generally references by name only. They can only appear in expressions, and the query operator under which the expression appears determines the table or tabular data stream.

Identifier naming rules

Identifiers are used to name various entities (entities or otherwise). Valid identifier names follow these rules:

• They have between 1 and 1024 characters long.
• They may contain letters, digits, underscores (_), spaces, dots (.), and dashes (-)
• Identifiers consisting only of letters, digits, and underscores do not require quoting when the identifier is being referenced.
• Identifiers containing at least one of (spaces, dots, or dashes) do require quoting.
• They are case-sensitive.

Identifier quoting

Identifiers that are identical to some query language keywords, or have one of the special characters noted above, require quoting when they are referenced directly by a query:

Query Text	Comments
unescaped	entities that do not include special characters or map to some language keyword require no quoting
[‘escaped’]	entities that include special characters in the name or the entity like a reserved word (“project” or “where”)