korma.core

Core querying and entity functions

*exec-mode*

dynamic

add-joins

(add-joins query ent rel)(add-joins query ent rel type)

aggregate

macro

(aggregate query agg alias & [group-by])
Use a SQL aggregator function, aliasing the results, and optionally grouping by
a field:

(select users
  (aggregate (count :*) :cnt :status))

Aggregates available: count, sum, avg, min, max, first, last

as-sql

(as-sql query)
Force a query to return a string of SQL when (exec) is called.

assoc-db-to-entity

(assoc-db-to-entity query ent)

belongs-to

macro

(belongs-to ent sub-ent & [opts])
Add a belongs-to relationship for the given entity. It is assumed that the foreign key
is on the current entity with the format sub-ent-table_id: email.user_id = user.id.
Can optionally pass a map with a :fk key to explicitly set the foreign key.

(belongs-to users email {:fk :emailID})

create-entity

(create-entity table)
Create an entity representing a table in a database.

create-relation

(create-relation ent sub-ent type opts)

database

(database ent db)
Set the database connection to be used for this entity.

defentity

macro

(defentity ent & body)
Define an entity representing a table in the database, applying any modifications in
the body.

delete

macro

(delete ent & body)
Creates a delete query, applies any modifying functions in the body and then
executes it. `ent` is either a string or an entity created by defentity.
Returns number of deleted rows as provided by the JDBC driver.

ex: (delete user
      (where {:id 7}))

delete*

(delete* ent)
Create an empty delete query. Ent can either be an entity defined by defentity,
or a string of the table name

dry-run

macro

(dry-run & body)
Wrap around a set of queries to print to the console all SQL that would
be run and return dummy values instead of executing them.

empty-query

(empty-query ent)

entity-fields

(entity-fields ent & fields)
Set the fields to be retrieved in all select queries for the
entity.

entity?

(entity? x)

exec

(exec query)
Execute a query map and return the results.

exec-raw

(exec-raw conn? & [sql with-results?])
Execute a raw SQL string, supplying whether results should be returned. `sql`
can either be a string or a vector of the sql string and its params. You can
also optionally provide the connection to execute against as the first
parameter.

(exec-raw ["SELECT * FROM users WHERE age > ?" [5]] :results)

fields

(fields query & vs)
Set the fields to be selected in a query. Fields can either be a keyword
or a vector of two keywords [field alias]:

(fields query :name [:firstname :first])

from

(from query table)
Add tables to the from clause.

get-rel

(get-rel ent sub-ent)

group

(group query & fields)
Add a group-by clause to a select query

has-many

macro

(has-many ent sub-ent & [opts])
Add a has-many relation for the given entity. It is assumed that the foreign key
is on the sub-entity with the format table_id: user.id = email.user_id
Can optionally pass a map with a :fk key to explicitly set the foreign key.

(has-many users email {:fk :emailID})

has-one

macro

(has-one ent sub-ent & [opts])
Add a has-one relationship for the given entity. It is assumed that the foreign key
is on the sub-entity with the format table_id: user.id = address.user_id
Can optionally pass a map with a :fk key to explicitly set the foreign key.

(has-one users address {:fk :userId})

having

macro

(having query form)
Add a having clause to the query, expressing the clause in clojure expressions
with keywords used to reference fields.
e.g. (having query (or (= :hits 1) (> :hits 5)))

Available predicates: and, or, =, not=, <, >, <=, >=, in, like, not, between

Having can also take a map at any point and will create a clause that compares
keys to values. The value can be a vector with one of the above predicate
functions describing how the key is related to the value:
  (having query {:name [like "chris"})

Having only works if you have an aggregation, using it without one will cause
an error.

having*

(having* query clause)
Add a having clause to the query. Clause can be either a map or a string, and
will be AND'ed to the other clauses.

insert

macro

(insert ent & body)
Creates an insert query, applies any modifying functions in the body
and then executes it. `ent` is either a string or an entity created by
defentity. The return value is the last inserted item, but its
representation is dependent on the database driver used
(e.g. postgresql returns the full row as a hash while MySQL and MSSQL
both return a {:generated_key <ID>} hash)

ex: (insert user
      (values [{:name "chris"} {:name "john"}]))

insert*

(insert* ent)
Create an empty insert query. Ent can either be an entity defined by defentity,
or a string of the table name

intersect

macro

(intersect & body)
Creates an intersect query, applies any modifying functions in the body and then
executes it.

ex: (intersect
      (queries (subselect user
                 (where {:id 7}))
               (subselect user-backup
                 (where {:id 8})))
      (order :name))

intersect*

(intersect*)
Create an empty intersect query.

join

macro

(join query ent)(join query type-or-table ent-or-clause)(join query type table clause)
Add a join clause to a select query, specifying an entity defined by defentity, or the table name to
join and the predicate to join on. If the entity relationship uses a join
table then two clauses will be added. Otherwise, only one clause
will be added.

(join query addresses)
(join query :right addresses)
(join query addresses (= :addres.users_id :users.id))
(join query :right addresses (= :address.users_id :users.id))

join*

(join* query type table clause)

limit

(limit query v)
Add a limit clause to a select query.

many-to-many

macro

(many-to-many ent sub-ent join-table & [opts])
Add a many-to-many relation for the given entity.  It is assumed that a join
table is used to implement the relationship and that the foreign keys are in
the join table.

many-to-many-fn

(many-to-many-fn ent sub-ent-var join-table opts)

modifier

(modifier query & modifiers)
Add a modifer to the beginning of a query:

(select orders
  (modifier "DISTINCT"))

offset

(offset query v)
Add an offset clause to a select query.

order

(order query field dir)(order query field)
Add an ORDER BY clause to a select, union, union-all, or intersect query.
field should be a keyword of the field name, dir is ASC by default.

(order query :created :asc)

pk

(pk ent pk)
Set the primary key used for an entity. :id by default.

post-query

(post-query query post)
Add a function representing a query that should be executed for each result
in a select. This is done lazily over the result set.

prepare

(prepare ent func)
Add a function to be applied to records/values going into the database

queries

(queries query & queries)
Adds a group of queries to a union, union-all or intersect

query-only

macro

(query-only & body)
Wrap around a set of queries to force them to return their query objects.

raw

(raw s)
Embed a raw string of SQL in a query. This is used when Korma doesn't
provide some specific functionality you're looking for:

(select users
  (fields (raw "PERIOD(NOW(), NOW())")))

rel

(rel ent sub-ent type opts)

select

macro

(select ent & body)
Creates a select query, applies any modifying functions in the body and then
executes it. `ent` is either a string or an entity created by defentity.

ex: (select user
      (fields :name :email)
      (where {:id 2}))

select*

(select* ent)
Create a select query with fields provided in Ent.  If fields are not provided,
create an empty select query. Ent can either be an entity defined by defentity,
or a string of the table name

set-fields

(set-fields query fields-map)
Set the fields and values for an update query.

sql-only

macro

(sql-only & body)
Wrap around a set of queries so that instead of executing, each will return a
string of the SQL that would be used.

sqlfn

macro

(sqlfn func & params)
Call an arbitrary SQL function by providing func as a symbol or keyword
and its params

sqlfn*

(sqlfn* fn-name & params)
Call an arbitrary SQL function by providing the name of the function
and its params

subselect

macro

(subselect & parts)
Create a subselect clause to be used in queries. This works exactly like
(select ...) execept it will wrap the query in ( .. ) and make sure it can be
used in any current query:

(select users
  (where {:id [in (subselect users2 (fields :id))]}))

table

(table ent t & [alias])
Set the name of the table and an optional alias to be used for the entity.
By default the table is the name of entity's symbol.

transform

(transform ent func)
Add a function to be applied to results coming from the database

union

macro

(union & body)
Creates a union query, applies any modifying functions in the body and then
executes it.

ex: (union
      (queries (subselect user
                 (where {:id 7}))
               (subselect user-backup
                 (where {:id 7})))
      (order :name))

union*

(union*)
Create an empty union query.

union-all

macro

(union-all & body)
Creates a union-all query, applies any modifying functions in the body and then
executes it.

ex: (union-all
      (queries (subselect user
                 (where {:id 7}))
               (subselect user-backup
                 (where {:id 7})))
      (order :name))

union-all*

(union-all*)
Create an empty union-all query.

update

macro

(update ent & body)
Creates an update query, applies any modifying functions in the body and then
executes it. `ent` is either a string or an entity created by defentity.
Returns number of updated rows as provided by the JDBC driver.

ex: (update user
      (set-fields {:name "chris"})
      (where {:id 4}))

update*

(update* ent)
Create an empty update query. Ent can either be an entity defined by defentity,
or a string of the table name.

values

(values query values)
Add records to an insert clause. values can either be a vector of maps or a
single map.

(values query [{:name "john"} {:name "ed"}])

where

macro

(where query form)
Add a where clause to the query, expressing the clause in clojure expressions
with keywords used to reference fields.
e.g. (where query (or (= :hits 1) (> :hits 5)))

Available predicates: and, or, =, not=, <, >, <=, >=, in, like, not, between

Where can also take a map at any point and will create a clause that compares keys
to values. The value can be a vector with one of the above predicate functions
describing how the key is related to the value:
  (where query {:name [like "chris"]})

where*

(where* query clause)
Add a where clause to the query. Clause can be either a map or a string, and
will be AND'ed to the other clauses.

with

macro

(with query ent & body)
Add a related entity to the given select query. If the entity has a relationship
type of :belongs-to or :has-one, the requested fields will be returned directly in
the result map. If the entity is a :has-many, a second query will be executed lazily
and a key of the entity name will be assoc'd with a vector of the results.

(defentity email (entity-fields :email))
(defentity user (has-many email))
(select user
  (with email) => [{:name "chris" :email [{email: "c@c.com"}]} ...

With can also take a body that will further refine the relation:
(select user
   (with address
      (with state)
      (fields :address.city :state.state)
      (where {:address.zip x})))

with*

(with* query sub-ent body-fn)

with-batch

macro

(with-batch query ent & body)
Add a related entity. This behaves like `with`, except that, for has-many
relationships, it runs a single query to get relations of all fetched rows.
This is faster than regular `with` but it doesn't support many of the
additional options (order, limit, offset, group, having)

with-batch*

(with-batch* query sub-ent body-fn)