From 2574e7e37f7807507085b47eb140d1127b4c8129 Mon Sep 17 00:00:00 2001
From: Sean Corfield <sean@corfield.org>
Date: Tue, 31 Mar 2020 11:58:45 -0700
Subject: [PATCH] Note MySQL handling of BLOB

---
 CHANGELOG.md           | 1 +
 doc/tips-and-tricks.md | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 49143f3..ff9270a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ Only accretive/fixative changes will be made from now on.
 
 The following changes have been made to **master** since the 1.0.409 build:
 
+* In **Tips & Tricks**, noted that MySQL returns `BLOB` columns as `byte[]` instead of `java.sql.Blob`.
 * Fixes #102 by allowing keywords or strings in `:return-keys`.
 * Fixes #101 by tightening the spec on a JDBC URL to correctly reflect that it must start with `jdbc:`.
 * Add support for calling `.getLoginTimeout`/`.setLoginTimeout` on the reified `DataSource` returned by `get-datasource` when called on a hash map "db-spec" or JDBC URL string.
diff --git a/doc/tips-and-tricks.md b/doc/tips-and-tricks.md
index 0d10f0e..7b248e6 100644
--- a/doc/tips-and-tricks.md
+++ b/doc/tips-and-tricks.md
@@ -4,7 +4,7 @@ This page contains various tips and tricks that make it easier to use `next.jdbc
 
 ## CLOB & BLOB SQL Types
 
-Columns declared with the `CLOB` or `BLOB` SQL types are typically rendered into Clojure result sets as database-specific custom types but they will implement `java.sql.Clob` or `java.sql.Blob` (as appropriate). In general, you can only read the data out of those Java objects during the current transaction, which effectively means that you need to do it either inside the reduction (for `plan`) or inside the result set builder (for `execute!` or `execute-one!`). If you always treat these types the same way for all columns across the whole of your application, you could simply extend `next.jdbc.result-set/ReadableColumn` to `java.sql.Clob` (and/or `java.sql.Blob`). Here's an example for reading `CLOB` into a `String`:
+Columns declared with the `CLOB` or `BLOB` SQL types are typically rendered into Clojure result sets as database-specific custom types but they should implement `java.sql.Clob` or `java.sql.Blob` (as appropriate). In general, you can only read the data out of those Java objects during the current transaction, which effectively means that you need to do it either inside the reduction (for `plan`) or inside the result set builder (for `execute!` or `execute-one!`). If you always treat these types the same way for all columns across the whole of your application, you could simply extend `next.jdbc.result-set/ReadableColumn` to `java.sql.Clob` (and/or `java.sql.Blob`). Here's an example for reading `CLOB` into a `String`:
 
 ```clojure
 (extend-protocol rs/ReadableColumn
@@ -36,6 +36,8 @@ No helper or column reader is provided for `BLOB` data since it is expected that
 
 Consult the [java.sql.Blob documentation](https://docs.oracle.com/javase/8/docs/api/java/sql/Blob.html) for more ways to process it.
 
+> Note: the standard MySQL JDBC driver seems to return `BLOB` data as `byte[]` instead of `java.sql.Blob`.
+
 ## MS SQL Server
 
 In MS SQL Server, the generated key from an insert comes back as `:GENERATED_KEYS`.