Identifiers

Identifiers are names for objects and entities in the databases. In SQL grammar, the naming rules for an identifier include:

• Begin with a Unicode letter or an underscore (_). Subsequent characters can be letters, underscore (_), or digits (0-9).
• Must be not identical to any SQL keyword unless the keyword is accepted by the element's syntax. For example, name accepts unreserved keywords or column name keywords.

To bypass either of these rules, simply surround the identifier with double quotes (" "). You can also use double quotes to preserve case-sensitivity in database, table, view, and column names.

Use Idenfifiers as Qualifiers

KWDB supports names composed of one or more identifiers, separated by the period character (.). The initial part of a composite name serves as a qualifier, influencing the interpretation of subsequent identifiers within the context.

You can reference columns using any of the methods listed in the table below:

Column Reference	Description
column_name	Reference the column_name column in any table.
table_name.column_name	Reference the column_name column in the table_name table within the current database.
database_name.table_name.column_name	Reference the column_name column in the table_name table within the database_name database.
column_name	Reference any keywords or fields with special characters.

When referencing composite identifiers, each individual identifier component must be quoted separately rather than treating the entire composite identifier as a single entity. For example, "table"."column" is a valid reference format, whereas "table.column" is invalid.

In most column reference statements, you do not need to explicitly specify table names or database names unless there is ambiguity in the target field. For example, if both t1 and t2 tables contain a column c, a SELECT statement retrieving column c from both t1 and t2 tables requires disambiguation by explicitly specifying t1.c or t2.c. Similarly, if two databases contain tables with identical names, you must use formats like db1.table_name.col_name and db2.table_name.col_name to precisely identify the target column.