dbUnquoteIdentifier {DBI}R Documentation

Unquote identifiers


Call this method to convert a SQL object created by dbQuoteIdentifier() back to a list of Id objects.


dbUnquoteIdentifier(conn, x, ...)



A DBIConnection object, as returned by dbConnect().


An SQL or Id object.


Other arguments passed on to methods.


dbUnquoteIdentifier() returns a list of objects 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 first element of a returned object again to dbUnquoteIdentifier() as x argument, it is returned unchanged (but wrapped in a list). Passing objects of class Id should also return them unchanged (but wrapped in a list). (For backends it may be most convenient to return Id objects to achieve this behavior, but this is not required.)

Failure modes

An error is raised if plain character vectors are passed as the x argument.


For any character vector of length one, quoting (with dbQuoteIdentifier()) then unquoting then quoting the first element is identical to just quoting. This is also true for strings 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.

Unquoting simple strings (consisting of only letters) wrapped with SQL() and then quoting via dbQuoteIdentifier() gives the same result as just quoting the string. Similarly, unquoting expressions of the form SQL("schema.table") and then quoting gives the same result as quoting the identifier constructed by Id(schema = "schema", table = "table").

See Also

Other DBIResult generics: DBIResult-class, dbBind(), dbClearResult(), dbColumnInfo(), dbFetch(), dbGetInfo(), dbGetRowCount(), dbGetRowsAffected(), dbGetStatement(), dbHasCompleted(), dbIsReadOnly(), dbIsValid(), dbQuoteIdentifier(), dbQuoteLiteral(), dbQuoteString()


# Unquoting allows to understand the structure of a
# possibly complex quoted identifier
  SQL(c('"Catalog"."Schema"."Table"', '"Schema"."Table"', '"UnqualifiedTable"'))

# The returned object is always a list,
# also for Id objects
  Id(catalog = "Catalog", schema = "Schema", table = "Table")

# Quoting is the inverse operation to unquoting the elements
# of the returned list
  dbUnquoteIdentifier(ANSI(), SQL("UnqualifiedTable"))[[1]]

  dbUnquoteIdentifier(ANSI(), Id(schema = "Schema", table = "Table"))[[1]]

[Package DBI version 1.1.3 Index]