Function reference • dm

Unique keys are similar to primary keys. Each table can have at most one record for each combination of values in a unique key. A table can have more than one unique key.

dm_add_uk(): Add a unique key

dm_get_all_uks(): Get all unique keys of a dm object

dm_rm_uk(): Remove a unique key

Foreign keys

Foreign keys establish links between tables by pointing to a primary or unique key in another table. See also vignette("howto-dm-theory").

dm_add_fk(): Add foreign keys

dm_get_all_fks(): Get foreign key constraints

dm_rm_fk(): Remove foreign keys

Visualize

Show a dm object, see also vignette("tech-dm-draw").

dm_gui(): Shiny app for defining dm objects

dm_draw(): Draw a diagram of the data model

dm_set_colors() dm_get_colors() dm_get_available_colors(): Color in database diagrams

dm_set_table_description() dm_get_table_description() dm_reset_table_description(): Add info about a dm's tables

Deconstruct

Rip a dm object apart and put it together, see also vignette("tech-dm-keyed").

dm_deconstruct(): Create code to deconstruct a dm object

Flatten

Combine multiple related tables, see also vignette("tech-dm-join").

dm_flatten_to_tbl(): Flatten a part of a dm into a wide table

dm_disambiguate_cols(): Resolve column name ambiguities

Filter

Filter across multiple tables, see also vignette("tech-dm-filter").

dm_filter(): Filtering

Zoom

Focus on a single table, see also vignette("tech-dm-zoom").

dm_zoom_to() dm_insert_zoomed() dm_update_zoomed() dm_discard_zoomed(): Mark table for manipulation

left_join(<dm_zoomed>) left_join(<dm_keyed_tbl>) inner_join(<dm_zoomed>) inner_join(<dm_keyed_tbl>) full_join(<dm_zoomed>) full_join(<dm_keyed_tbl>) right_join(<dm_zoomed>) right_join(<dm_keyed_tbl>) semi_join(<dm_zoomed>) semi_join(<dm_keyed_tbl>) anti_join(<dm_zoomed>) anti_join(<dm_keyed_tbl>) nest_join(<dm_zoomed>): dplyr join methods for zoomed dm objects

filter(<dm_zoomed>) mutate(<dm_zoomed>) transmute(<dm_zoomed>) select(<dm_zoomed>) relocate(<dm_zoomed>) rename(<dm_zoomed>) distinct(<dm_zoomed>) arrange(<dm_zoomed>) slice(<dm_zoomed>) group_by(<dm_zoomed>) group_by(<dm_keyed_tbl>) ungroup(<dm_zoomed>) summarise(<dm_zoomed>) summarise(<dm_keyed_tbl>) count(<dm_zoomed>) tally(<dm_zoomed>) pull(<dm_zoomed>) compute(<dm_zoomed>): dplyr table manipulation methods for zoomed dm objects

glimpse(<dm>) glimpse(<dm_zoomed>): Get a glimpse of your dm object

unite(<dm_zoomed>) unite(<dm_keyed_tbl>) separate(<dm_zoomed>) separate(<dm_keyed_tbl>): tidyr table manipulation methods for zoomed dm objects

head(<dm_zoomed>) tail(<dm_zoomed>): utils table manipulation methods for dm_zoomed objects

Wrap

Turn a dm object into a single table and back.

dm_wrap_tbl(): Wrap dm into a single tibble dm

dm_unwrap_tbl(): Unwrap a single table dm

dm_nest_tbl(): Nest a table inside its dm

dm_pack_tbl(): dm_pack_tbl()

dm_unnest_tbl(): Unnest columns from a wrapped table

dm_unpack_tbl(): Unpack columns from a wrapped table

Nested and packed data

New verbs that power wrapping.

pack_join(): Pack Join

json_nest(): JSON nest

json_nest_join(): JSON nest join

json_pack(): JSON pack

json_pack_join(): JSON pack join

json_unnest(): Unnest a JSON column

json_unpack(): Unpack a JSON column

Materialize and upload

Get data from and to the database, see also vignette("howto-dm-copy").

compute(<dm>) collect(<dm>): Materialize

copy_dm_to(): Copy data model to data source

dm_sql() dm_ddl_pre() dm_dml_load() dm_ddl_post(): Create DDL and DML scripts for a dm a and database connection

Modify

Manipulate individual rows on the database, see also vignette("howto-dm-rows").

dm_rows_insert() dm_rows_append() dm_rows_update() dm_rows_patch() dm_rows_upsert() dm_rows_delete(): Modifying rows for multiple tables

Keys and cardinalities

Check fulfillment and nature of relationships between tables.

dm_examine_constraints(): Validate your data model

enum_pk_candidates() dm_enum_pk_candidates(): Primary key candidate

dm_enum_fk_candidates() enum_fk_candidates(): Foreign key candidates

dm_examine_cardinalities(): Learn about your data model

check_cardinality_0_n() check_cardinality_1_n() check_cardinality_1_1() check_cardinality_0_1() examine_cardinality(): Check table relations

check_key(): Check if column(s) can be used as keys

check_set_equality(): Check column values for set equality

check_subset(): Check column values for subset

Table surgery

Normalize and denormalize tables.

decompose_table(): Decompose a table into two linked tables

reunite_parent_child() reunite_parent_child_from_list(): Merge two tables that are linked by a foreign key relation

Database schemas

New verbs that power access to database schemas.

db_schema_create(): Create a schema on a database

db_schema_drop(): Remove a schema from a database

db_schema_exists(): Check for existence of a schema on a database

db_schema_list(): List schemas on a database

Example dm objects

Ready to use and play with.

dm_nycflights13(): Creates a dm object for the nycflights13 data

dm_financial() dm_financial_sqlite(): Creates a dm object for the Financial data

dm_pixarfilms(): Creates a dm object for the pixarfilms data

Structure and contents

Recreate a dm object.

dm_paste(): Create R code for a dm object

dm_ptype(): Prototype for a dm object