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First cut at RowBuilder

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Temporarily disables as-arrays
This commit is contained in:
Sean Corfield 2019-04-10 23:59:19 -07:00
parent eefea54358
commit 788015909f
3 changed files with 94 additions and 59 deletions
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14
src/next/jdbc.clj
View file

@ -148,9 +148,9 @@
([stmt]
(rs/execute! stmt [] (partial into {}) {}))
([connectable sql-params]
(rs/execute! connectable sql-params (rs/datafiable-row connectable {}) {}))
(rs/execute! connectable sql-params #(rs/datafiable-row % connectable {}) {}))
([connectable sql-params opts]
(rs/execute! connectable sql-params (rs/datafiable-row connectable opts) opts))
(rs/execute! connectable sql-params #(rs/datafiable-row % connectable opts) opts))
([connectable sql-params f opts]
(rs/execute! connectable sql-params f opts)))
@ -167,9 +167,9 @@
([stmt]
(rs/execute-one! stmt [] (partial into {}) {}))
([connectable sql-params]
(rs/execute-one! connectable sql-params (rs/datafiable-row connectable {}) {}))
(rs/execute-one! connectable sql-params #(rs/datafiable-row % connectable {}) {}))
([connectable sql-params opts]
(rs/execute-one! connectable sql-params (rs/datafiable-row connectable opts) opts))
(rs/execute-one! connectable sql-params #(rs/datafiable-row % connectable opts) opts))
([connectable sql-params f opts]
(rs/execute-one! connectable sql-params f opts)))
@ -240,7 +240,7 @@
opts)
(rs/execute! connectable
sql-params
(rs/datafiable-row connectable opts)
#(rs/datafiable-row % connectable opts)
opts))))
(defn find-by-keys
@ -258,7 +258,7 @@
opts)
(rs/execute! connectable
(sql/for-query table key-map opts)
(rs/datafiable-row connectable opts)
#(rs/datafiable-row % connectable opts)
opts))))
(defn get-by-id
@ -281,7 +281,7 @@
opts)
(rs/execute-one! connectable
(sql/for-query table {pk-name pk} opts)
(rs/datafiable-row connectable opts)
#(rs/datafiable-row % connectable opts)
opts))))
(defn update!

109
src/next/jdbc/result_set.clj
View file

@ -12,12 +12,12 @@
(set! *warn-on-reflection* true)
(defn- get-column-names
"Given a ResultSet, return a vector of columns names, each qualified by
"Given ResultSetMetaData, return a vector of columns names, each qualified by
the table from which it came.
If :identifiers was specified, apply that to both the table qualifier
and the column name."
[^ResultSet rs ^ResultSetMetaData rsmeta opts]
[^ResultSetMetaData rsmeta opts]
(let [idxs (range 1 (inc (.getColumnCount rsmeta)))]
(if-let [ident-fn (:identifiers opts)]
(mapv (fn [^Integer i]
@ -30,12 +30,6 @@
(.getColumnLabel rsmeta i)))
idxs))))
(defprotocol ColumnarResultSet
"To allow reducing functions to access a result set's column names and
row values, such as the as-arrays reducing function in this namespace."
(column-names [this] "Return the column names from a result set.")
(row-values [this] "Return the values from the current row of a result set."))
(defprotocol ReadableColumn
"Protocol for reading objects from the java.sql.ResultSet. Default
implementations (for Object and nil) return the argument, and the
@ -59,6 +53,37 @@
(read-column-by-label [_1 _2] nil)
(read-column-by-index [_1 _2 _3] nil))
(defprotocol RowBuilder
"Protocol for building rows in various representations:
row -- called once per row to create the basis of each row
columns -- return the number of columns in each row
with-column -- called with the index of the column to be added
build -- called once per row to finalize each row once it is complete"
(row [_])
(columns [_])
(with-column [_ row i])
(build [_ row]))
(defn map-row-builder [^ResultSet rs opts]
(let [rsmeta (.getMetaData rs)
cols (get-column-names rsmeta opts)]
(reify
RowBuilder
(row [this] (transient {}))
(columns [this] (count cols))
(with-column [this row i]
(assoc! row
(nth cols (dec i))
(read-column-by-index (.getObject rs ^Integer i) rsmeta i)))
(build [this row] (persistent! row)))))
(declare navize-row)
(defprotocol DatafiableRow
"Given a connectable object, return a function that knows how to turn a row
into a datafiable object that can be 'nav'igated."
(datafiable-row [this connectable opts]))
(defn- mapify-result-set
"Given a result set, return an object that wraps the current row as a hash
map. Note that a result set is mutable and the current row will change behind
@ -71,8 +96,12 @@
Supports Seqable which realizes a full row of the data."
[^ResultSet rs opts]
(let [rsmeta (.getMetaData rs)
cols (delay (get-column-names rs rsmeta opts))]
(let [gen (when-let [gen-fn (:gen-fn opts)] (gen-fn rs opts))
row-builder (fn [] ; blows up if :gen-fn not provided
(->> (reduce (fn [r i] (with-column gen r i))
(row gen)
(range 1 (inc (columns gen))))
(build gen)))]
(reify
clojure.lang.ILookup
@ -100,27 +129,28 @@
(name k)))
(catch SQLException _)))
(assoc [this k v]
(assoc (into {} (seq this)) k v))
(assoc (row-builder) k v))
clojure.lang.Seqable
(seq [this]
(seq (mapv (fn [^Integer i]
(clojure.lang.MapEntry. (nth @cols (dec i))
(read-column-by-index
(.getObject rs i)
rsmeta i)))
(range 1 (inc (count @cols))))))
(seq (row-builder)))
ColumnarResultSet
(column-names [this] @cols)
(row-values [this]
(mapv (fn [^Integer i] (read-column-by-index
(.getObject rs i)
rsmeta i))
(range 1 (inc (count @cols))))))))
DatafiableRow
(datafiable-row [this connectable opts]
(with-meta
(row-builder)
{`core-p/datafy (navize-row connectable opts)})))))
(defn as-arrays
"A reducing function that can be used on a result set to produce an
(extend-protocol
DatafiableRow
clojure.lang.IObj
(datafiable-row [this connectable opts]
(with-meta
this
{`core-p/datafy (navize-row connectable opts)})))
#_(defn as-arrays
"A reducing function that can be used on a result set to produce an
array-based representation, where the first element is a vector of the
column names in the result set, and subsequent elements are vectors of
the rows from the result set.
@ -128,10 +158,10 @@
It should be used with a nil initial value:
(reduce rs/as-arrays nil (reducible! con sql-params))"
[result rs-map]
(if result
(conj result (row-values rs-map))
(conj [(column-names rs-map)] (row-values rs-map))))
[result rs-map]
(if result
(conj result (row-values rs-map))
(conj [(column-names rs-map)] (row-values rs-map))))
(defn- reduce-stmt
"Execute the PreparedStatement, attempt to get either its ResultSet or
@ -190,15 +220,6 @@
(-execute [this sql-params opts]
(p/-execute (p/get-datasource this) sql-params opts)))
(declare navize-row)
(defn datafiable-row
"Given a connectable object, return a function that knows how to turn a row
into a datafiable object that can be 'nav'igated."
[connectable opts]
(fn [row]
(into (with-meta {} {`core-p/datafy (navize-row connectable opts)}) row)))
(defn execute!
"Given a connectable object and SQL and parameters, execute it and reduce it
into a vector of processed hash maps (rows).
@ -207,7 +228,9 @@
[connectable sql-params f opts]
(into []
(map f)
(p/-execute connectable sql-params opts)))
(p/-execute connectable
sql-params
(update opts :gen-fn #(or % map-row-builder)))))
(defn execute-one!
"Given a connectable object and SQL and parameters, execute it and return
@ -217,7 +240,9 @@
[connectable sql-params f opts]
(reduce (fn [_ row] (reduced (f row)))
nil
(p/-execute connectable sql-params opts)))
(p/-execute connectable
sql-params
(update opts :gen-fn #(or % map-row-builder)))))
(defn- default-schema
"The default schema lookup rule for column names.
@ -265,7 +290,7 @@
(entity-fn (name fk))
" = ?")
v]
(datafiable-row connectable opts)
#(datafiable-row % connectable opts)
opts))
(catch Exception _
;; assume an exception means we just cannot

30
test/next/jdbc_test.clj
View file

@ -61,6 +61,12 @@
["select * from fruit where appearance = ?" "red"]
:name
{}))
(quick-bench
(execute-one! con
["select * from fruit where appearance = ?" "red"]
:name ; turn off row builder as we don't need it
;; this gives a very slight improvement
{:gen-fn (constantly nil)}))
;; 5.7 micros -- 3.7x
(quick-bench
(jdbc/query {:connection con}
@ -79,10 +85,12 @@
(execute! con ["select * from fruit"]))
;; this is not quite equivalent
(quick-bench ; 5.34-5.4
(into [] (map (partial into {})) (reducible! con ["select * from fruit"])))
(into [] (map (partial into {})) (reducible! con ["select * from fruit"]
{:gen-fn rs/map-row-builder})))
;; but this is (equivalent to execute!)
(quick-bench ; 5.58-5.8
(into [] (map (rs/datafiable-row con {})) (reducible! con ["select * from fruit"])))
(into [] (map #(rs/datafiable-row % con {})) (reducible! con ["select * from fruit"]
{:gen-fn rs/map-row-builder})))
(quick-bench ; 7.84-7.96 -- 1.3x
(jdbc/query {:connection con} ["select * from fruit"]))
@ -137,16 +145,18 @@
(execute-one! con ["select * from fruit where appearance = ?" "red"]))
;; test assoc works
(execute-one! con
["select * from fruit where appearance = ?" "red"]
#(assoc % :test :value)
{})
(quick-bench
(execute-one! con
["select * from fruit where appearance = ?" "red"]
#(assoc % :test :value)
{}))
;; test assoc works
(execute! con
["select * from fruit where appearance = ?" "red"]
#(assoc % :test :value)
{})
(quick-bench
(execute! con
["select * from fruit where appearance = ?" "red"]
#(assoc % :test :value)
{}))
(with-transaction [t con {:rollback-only true}]
(insert! t :fruit {:id 5, :name "Pear", :appearance "green", :cost 49, :grade 47})