fix #406

CHANGELOG.md

@@ -6,6 +6,7 @@
   * Address [#414](https://github.com/seancorfield/honeysql/issues/414) by providing an example of `ORDER BY` with a `CASE` expression.
   * Address [#412](https://github.com/seancorfield/honeysql/issues/412) by documenting options in a separate page and reorganizing the ToC structure.
   * Address [#409](https://github.com/seancorfield/honeysql/issues/409) by making docstring check for public helpers conditional.
+  * Fix [#406](https://github.com/seancorfield/honeysql/issues/406) by adding `:alter-column` (which produces `MODIFY COLUMN` when the MySQL dialect is selected) and deprecating `:modify-column`.
   * Address [#401](https://github.com/seancorfield/honeysql/issues/401) by adding `register-dialect!` and `get-dialect`, and also making `add-clause-before`, `strop`, and `upper-case` public so that new dialects are easier to construct.
 
 * 2.2.891 -- 2022-04-23

doc/clause-reference.md

@@ -32,7 +32,7 @@ See [Column Descriptors in Special Syntax](special-syntax.md#column-descriptors)
 
 > Google BigQuery support: `[:bigquery/array :string]` as a column type produces `ARRAY<STRING>` and `[:bigquery/struct col1-spec col2-spec]` as a column type produces `STRUCT<col1, col2>` (where `colN-spec` is a vector specifying a named column).
 
-## alter-table, add-column, drop-column, modify-column, rename-column
+## alter-table, add-column, drop-column, alter-column, modify-column, rename-column
 
 `:alter-table` can accept either a single table name or
 a sequence that begins with a table name and is followed
@@ -55,8 +55,8 @@ user=> (sql/format {:alter-table :fruit
                     :drop-column [:if-exists :ident]})
 ["ALTER TABLE fruit DROP COLUMN IF EXISTS ident"]
 user=> (sql/format {:alter-table :fruit
-                    :modify-column [:id :int :unsigned nil]})
+                    :alter-column [:id :int :unsigned nil]})
-["ALTER TABLE fruit MODIFY COLUMN id INT UNSIGNED NULL"]
+["ALTER TABLE fruit ALTER COLUMN id INT UNSIGNED NULL"]
 user=> (sql/format {:alter-table :fruit
                     :rename-column [:look :appearance]})
 ["ALTER TABLE fruit RENAME COLUMN look TO appearance"]
@@ -75,20 +75,22 @@ user=> (sql/format {:alter-table [:fruit
                                   {:add-column [:id :int [:not nil]]}
                                   {:add-column [:name [:varchar 32]]}
                                   {:drop-column :ident}
-                                  {:modify-column [:appearance :text]}]})
+                                  {:alter-column [:appearance :text]}]})
-["ALTER TABLE fruit ADD COLUMN id INT NOT NULL, ADD COLUMN name VARCHAR(32), DROP COLUMN ident, MODIFY COLUMN appearance TEXT"]
+["ALTER TABLE fruit ADD COLUMN id INT NOT NULL, ADD COLUMN name VARCHAR(32), DROP COLUMN ident, ALTER COLUMN appearance TEXT"]
 user=> (sql/format {:alter-table [:fruit
                                   {:add-column [:id :int [:not nil] :if-not-exists]}
                                   {:drop-column [:if-exists :ident]}]})
 ["ALTER TABLE fruit ADD COLUMN IF NOT EXISTS id INT NOT NULL, DROP COLUMN IF EXISTS ident"]
 ```
 
-As can be seen above, `:add-column` and `:modify-column`
+As can be seen above, `:add-column` and `:alter-column`
 both accept a column description (as a sequence of simple
 expressions); `:drop-column` accepts a single column name,
 and `:rename-column` accepts a sequence with two column
 names: the "from" and the "to" names.
 
+> Note: `:modify-column` is MySQL-specific and should be considered legacy and deprecated. `:alter-column` will produce `MODIFY COLUMN` when the MySQL dialect is selected.
+
 ### add-index, drop-index
 
 Used with `:alter-table`,

doc/postgresql.md

@@ -21,7 +21,7 @@ The code examples herein assume:
                                      insert-into values
                                      create-table with-columns create-view create-extension
                                      add-column alter-table add-index
-                                     modify-column rename-column rename-table
+                                     alter-column rename-column rename-table
                                      drop-table drop-column drop-index drop-extension
                                      upsert returning on-conflict on-constraint
                                      do-update-set do-nothing]])
@@ -361,11 +361,11 @@ user=> (-> (alter-table :fruit)
            (drop-column :skin)
            sql/format)
 ["ALTER TABLE fruit DROP COLUMN skin"]
-;; alter table modify column:
+;; alter table alter column:
 user=> (-> (alter-table :fruit)
-           (modify-column :name [:varchar 64] [:not nil])
+           (alter-column :name [:varchar 64] [:not nil])
            sql/format)
-["ALTER TABLE fruit MODIFY COLUMN name VARCHAR(64) NOT NULL"]
+["ALTER TABLE fruit ALTER COLUMN name VARCHAR(64) NOT NULL"]
 ;; alter table rename column:
 user=> (-> (alter-table :fruit)
            (rename-column :cost :price)

doc/special-syntax.md

@@ -4,7 +4,7 @@ This section lists the function-like expressions that
 HoneySQL supports out of the box which are formatted
 as special syntactic forms.
 
-The first group are used for SQL expressions. The second (last group) are used primarily in column definitions (as part of `:with-columns` and `:add-column` / `:modify-column`).
+The first group are used for SQL expressions. The second (last group) are used primarily in column definitions (as part of `:with-columns` and `:add-column` / `:alter-column`).
 
 ## array
 

src/honey/sql.cljc

@@ -42,7 +42,8 @@
 (def ^:private default-clause-order
   "The (default) order for known clauses. Can have items added and removed."
   [;; DDL comes first (these don't really have a precedence):
-   :alter-table :add-column :drop-column :modify-column :rename-column
+   :alter-table :add-column :drop-column
+   :alter-column :modify-column :rename-column
    :add-index :drop-index :rename-table
    :create-table :create-table-as :with-columns
    :create-view :create-materialized-view :create-extension
@@ -943,6 +944,10 @@
   (atom {:alter-table     #'format-alter-table
          :add-column      #'format-add-item
          :drop-column     #'format-drop-items
+         :alter-column    (fn [k spec]
+                            (format-add-item
+                             (if (mysql?) :modify-column k)
+                             spec))
          :modify-column   #'format-add-item
          :rename-column   #'format-rename-item
          ;; so :add-index works with both [:index] and [:unique]

src/honey/sql/helpers.cljc

@@ -179,11 +179,22 @@
   [& args]
   (generic-1 :drop-column args))
 
+(defn alter-column
+  "Like add-column, accepts any number of SQL elements
+  that describe the new column definition:
+
+  (alter-column :name [:varchar 64] [:not nil])"
+  [& col-elems]
+  (generic :alter-column col-elems))
+
 (defn modify-column
   "Like add-column, accepts any number of SQL elements
   that describe the new column definition:
 
-  (modify-column :name [:varchar 64] [:not nil])"
+  (modify-column :name [:varchar 64] [:not nil])
+
+  MySQL-specific, deprecated. Use `alter-column` and
+  specify the MySQL dialect to get `MODIFY COLUMN`."
   [& col-elems]
   (generic :modify-column col-elems))