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address #212

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Sean Corfield 2022-08-08 16:56:58 -07:00
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4
CHANGELOG.md
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@ -2,6 +2,10 @@
Only accretive/fixative changes will be made from now on.
* 1.2.next in progress
* Address [#212](https://github.com/seancorfield/next-jdbc/issues/212) by documenting the problem with SQLite's JDBC driver.
* Switch SQL Server testing setup to `docker-compose`.
* 1.2.796 -- 2022-08-01
* Make `Transactable` extensible via metadata, via PR [#209](https://github.com/seancorfield/next-jdbc/issues/209) -- [@vemv](https://github.com/vemv).
* Fix [#208](https://github.com/seancorfield/next-jdbc/issues/208) by treating unsupported exception as an empty string, just like the JDBC docs say should happen.

21
doc/datafy-nav-and-schema.md
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@ -81,3 +81,24 @@ If you require `next.jdbc.datafy`, the `Datafiable` protocol is extended to seve
See the Java documentation for these JDBC types for further details on what all the properties from each of these classes mean and which are `int`, `String`, or some other JDBC object type.
In addition, requiring this namespace will affect how `next.jdbc.result-set/metadata` behaves inside the reducing function applied to the result of `plan`. Without this namespace loaded, that function will return a raw `ResultSetMetaData` object (which must not leak outside the reducing function). With this namespace loaded, that function will, instead, return a Clojure data structure describing the columns in the result set.
### SQLite
For some strange reason, SQLite has implemented their `ResultSetMetaData` as also
being a `ResultSet` which leads to ambiguity when datafying some things when
using SQLite. `next.jdbc` currently assumes that if it is asked to `datafy` a
`ResultSet` and that object is _also_ `ResultSetMetaData`, it will treat it
purely as `ResultSetMetaData`, which produces a vector of column metadata as
described above. However, there are some results in SQLite's JDBC driver that
look like `ResultSetMetaData` but should be treated as plain `ResultSet`
objects (which is what other databases' JDBC drivers return).
An example of this is what happens when you try to `datafy` the result of
calling `DatabaseMetaData.getTables()`: the JDBC documentation says you get
back a `ResultSet` but in SQLite, that is also an instance of `ResultSetMetaData`
and so `next.jdbc.datafy` treats it that way instead of as a plain `ResultSet`.
You can call `next.jdbc.result-set/datafiable-result-set` directly in this
case to get the rows as a hash map (although you won't get the underlying
metadata as a bean).
See issue [#212](https://github.com/seancorfield/next-jdbc/issues/212) for more details.