spec_sql_quote_identifier
Value
dbQuoteIdentifier() returns an object that can be coerced to character,
of the same length as the input.
For an empty character vector this function returns a length-0 object.
The names of the input argument are preserved in the output.
When passing the returned object again to dbQuoteIdentifier()
as x
argument, it is returned unchanged.
Passing objects of class DBI::SQL should also return them unchanged.
(For backends it may be most convenient to return DBI::SQL objects
to achieve this behavior, but this is not required.)
Specification
Calling DBI::dbGetQuery() for a query of the format SELECT 1 AS ...
returns a data frame with the identifier, unquoted, as column name.
Quoted identifiers can be used as table and column names in SQL queries,
in particular in queries like SELECT 1 AS ...
and SELECT * FROM (SELECT 1) ....
The method must use a quoting mechanism that is unambiguously different
from the quoting mechanism used for strings, so that a query like
SELECT ... FROM (SELECT 1 AS ...)
throws an error if the column names do not match.
The method can quote column names that
contain special characters such as a space,
a dot,
a comma,
or quotes used to mark strings
or identifiers,
if the database supports this.
In any case, checking the validity of the identifier
should be performed only when executing a query,
and not by dbQuoteIdentifier().
See also
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table