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

Methods in other packages

  • RSQLite::dbUnquoteIdentifier("SQLiteConnection", "SQL")

dbUnquoteIdentifier(conn, x, ...)

Arguments

conn

A subclass of DBIConnection, representing an active connection to an DBMS.

x

An SQL or Id object or character vector to unquote.

...

Other arguments passed on to methods.

Value

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.)

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

Specification

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 gives the same result as just quoting.

See also

Examples

# Unquoting allows to understand the structure of a # possibly complex quoted identifier dbUnquoteIdentifier( ANSI(), SQL(c('"Schema"."Table"', '"UnqualifiedTable"')) )
#> [[1]] #> <Id> schema = Schema, table = Table #> #> [[2]] #> <Id> table = UnqualifiedTable #>
# The returned object is always a list, # also for Id objects dbUnquoteIdentifier( ANSI(), Id(schema = "Schema", table = "Table") )
#> [[1]] #> <Id> schema = Schema, table = Table #>
# Quoting is the inverse operation to unquoting the elements # of the returned list dbQuoteIdentifier( ANSI(), dbUnquoteIdentifier(ANSI(), SQL("UnqualifiedTable"))[[1]] )
#> <SQL> "UnqualifiedTable"
dbQuoteIdentifier( ANSI(), dbUnquoteIdentifier(ANSI(), Id(schema = "Schema", table = "Table"))[[1]] )
#> <SQL> "Schema"."Table"