gh-69093: Add indexing and slicing support to sqlite3.Blob (#91599)

Authored-by: Aviv Palivoda <palaviv@gmail.com>
Co-authored-by: Erlend E. Aasland <erlend.aasland@innova.no>

2 files changed, 11 insertions, 7 deletions

diff --git a/Doc/includes/sqlite3/blob.py b/Doc/includes/sqlite3/blob.py
index b3694ad..d947059 100644
--- a/Doc/includes/sqlite3/blob.py
+++ b/Doc/includes/sqlite3/blob.py
@@ -2,15 +2,18 @@ import sqlite3
 
 con = sqlite3.connect(":memory:")
 con.execute("create table test(blob_col blob)")
-con.execute("insert into test(blob_col) values (zeroblob(10))")
+con.execute("insert into test(blob_col) values (zeroblob(13))")
 
 # Write to our blob, using two write operations:
 with con.blobopen("test", "blob_col", 1) as blob:
-    blob.write(b"Hello")
-    blob.write(b"World")
+    blob.write(b"hello, ")
+    blob.write(b"world.")
+    # Modify the first and last bytes of our blob
+    blob[0] = b"H"
+    blob[-1] = b"!"
 
 # Read the contents of our blob
 with con.blobopen("test", "blob_col", 1) as blob:
     greeting = blob.read()
 
-print(greeting)  # outputs "b'HelloWorld'"
+print(greeting)  # outputs "b'Hello, world!'"
diff --git a/Doc/library/sqlite3.rst b/Doc/library/sqlite3.rst
index cbe7bb1..69e77e9 100644
--- a/Doc/library/sqlite3.rst
+++ b/Doc/library/sqlite3.rst
@@ -1051,9 +1051,10 @@ Blob Objects
 
 .. class:: Blob
 
-   A :class:`Blob` instance is a :term:`file-like object` that can read and write
-   data in an SQLite :abbr:`BLOB (Binary Large OBject)`.  Call ``len(blob)`` to
-   get the size (number of bytes) of the blob.
+   A :class:`Blob` instance is a :term:`file-like object`
+   that can read and write data in an SQLite :abbr:`BLOB (Binary Large OBject)`.
+   Call :func:`len(blob) <len>` to get the size (number of bytes) of the blob.
+   Use indices and :term:`slices <slice>` for direct access to the blob data.
 
    Use the :class:`Blob` as a :term:`context manager` to ensure that the blob
    handle is closed after use.