Returns the names of remote objects accessible through this connection
as a data frame.
This should include temporary objects, but not all database backends
(in particular RMariaDB and RMySQL) support this.
Compared to dbListTables(), this method also enumerates tables and views
in schemas, and returns fully qualified identifiers to access these objects.
This allows exploration of all database objects available to the current
user, including those that can only be accessed by giving the full
namespace.
dbListObjects(conn, prefix = NULL, ...)A DBIConnection object, as returned by
dbConnect().
A fully qualified path in the database's namespace, or NULL.
This argument will be processed with dbUnquoteIdentifier().
If given the method will return all objects accessible through this prefix.
Other parameters passed on to methods.
dbListObjects()
returns a data frame
with columns
table and is_prefix (in that order),
optionally with other columns with a dot (.) prefix.
The table column is of type list.
Each object in this list is suitable for use as argument in dbQuoteIdentifier().
The is_prefix column is a logical.
This data frame contains one row for each object (schema, table
and view)
accessible from the prefix (if passed) or from the global namespace
(if prefix is omitted).
Tables added with dbWriteTable()
are part of the data frame. As soon a table is removed from the database, it is also removed from the data frame of database objects.
The same applies to temporary objects if supported by the database.
The returned names are suitable for quoting with dbQuoteIdentifier().
An error is raised when calling this method for a closed or invalid connection.
The prefix column indicates if the table value refers to a table
or a prefix.
For a call with the default prefix = NULL, the table
values that have is_prefix == FALSE correspond to the tables
returned from dbListTables(),
The table object can be quoted with dbQuoteIdentifier().
The result of quoting can be passed to dbUnquoteIdentifier().
(We have to assume that the resulting identifier is a table, because one
cannot always tell from a quoted identifier alone whether it is a table
or a schema for example. As a consequence, the quote-unquote roundtrip
only works for tables (possibly schema-qualified), but not for other
database objects like schemata or columns.)
The unquoted results are equal to the original table object.
(For backends it may be convenient to use the Id class, but this is
not required.)
Values in table column that have is_prefix == TRUE can be
passed as the prefix argument to another call to dbListObjects().
For the data frame returned from a dbListObject() call with the
prefix argument set, all table values where is_prefix is
FALSE can be used in a call to dbExistsTable() which returns
TRUE.
Other DBIConnection generics:
DBIConnection-class,
dbAppendTable(),
dbCreateTable(),
dbDataType(),
dbDisconnect(),
dbExecute(),
dbExistsTable(),
dbGetException(),
dbGetInfo(),
dbGetQuery(),
dbIsReadOnly(),
dbIsValid(),
dbListFields(),
dbListResults(),
dbListTables(),
dbReadTable(),
dbRemoveTable(),
dbSendQuery(),
dbSendStatement(),
dbWriteTable()
con <- dbConnect(RSQLite::SQLite(), ":memory:")
dbListObjects(con)
#> [1] table is_prefix
#> <0 rows> (or 0-length row.names)
dbWriteTable(con, "mtcars", mtcars)
dbListObjects(con)
#> table is_prefix
#> 1 <Id> "mtcars" FALSE
dbDisconnect(con)