From 5425bc78bf1597be3ed7f5c0131953ef36e00995 Mon Sep 17 00:00:00 2001
From: Drew Bednar <drew@runcible.io>
Date: Sat, 20 Jul 2024 21:38:14 -0400
Subject: [PATCH] More useful notes

---
 .../try-sqlite/data/trysqlite.db-shm          | Bin 32768 -> 0 bytes
 .../try-sqlite/data/trysqlite.db-wal          |   0
 go-sql-database/try-sqlite/main.go            |  21 +++++++++++++++---
 3 files changed, 18 insertions(+), 3 deletions(-)
 delete mode 100644 go-sql-database/try-sqlite/data/trysqlite.db-shm
 delete mode 100644 go-sql-database/try-sqlite/data/trysqlite.db-wal

diff --git a/go-sql-database/try-sqlite/data/trysqlite.db-shm b/go-sql-database/try-sqlite/data/trysqlite.db-shm
deleted file mode 100644
index fe9ac2845eca6fe6da8a63cd096d9cf9e24ece10..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 32768
zcmeIuAr62r3<XeTSayS60=Z=O-0|kP2&fu@!6Du^ziFC^7w55MN)9hQYV3Wk79a2P
z)%8g3H30$y2oNAZfB*pk1PBlyK!5-N0t5&UAV7cs0RjXF5FkK+009C72oNAZfB*pk
z1PBlyK!5-N0t5&UAV7cs0RjXF5FkK+009C72oNAZfB*pk1PBlyK!5-N0t5&UAV7cs
w0RjXF5FkK+009C72oNAZfB*pk1PBlyK!5-N0t5&UAV7cs0RjXF5cq?@4dk5`Qvd(}

diff --git a/go-sql-database/try-sqlite/data/trysqlite.db-wal b/go-sql-database/try-sqlite/data/trysqlite.db-wal
deleted file mode 100644
index e69de29..0000000
diff --git a/go-sql-database/try-sqlite/main.go b/go-sql-database/try-sqlite/main.go
index ccc750c..934bd9f 100644
--- a/go-sql-database/try-sqlite/main.go
+++ b/go-sql-database/try-sqlite/main.go
@@ -94,6 +94,8 @@ func main() {
 	// If never want to do string concat from user input into a sql statement you run unless you like sql injection attacks
 	// expects to return one row. If no row it will delay throwing error until Scan is called
 	row := db.QueryRow("SELECT id, subject, todo FROM todos WHERE id = ?", 1)
+	// Scan does the heavily lifting for you when casting from db type to go type. It will cast based on the variable type.
+	// failures of course will be returned as part of the err
 	err = row.Scan(&id, &subject, &todo)
 	if err != nil {
 		log.Fatal(err)
@@ -102,13 +104,26 @@ func main() {
 	log.Printf("id: %d, subject: %s, todo: %s", id, subject, todo)
 
 	// This should error on scan
-
-	row = db.QueryRow("SELECT * FROM todos WHERE id = ?", 100_000)
-	err = row.Scan(&id, &subject, &todo)
+	// We can also use this short hand!
+	err = db.QueryRow("SELECT * FROM todos WHERE id = ?", 100_000).Scan(&id, &subject, &todo)
 	if err != nil {
 		log.Print(err.Error())
 	}
 
 	// There is no row.Close(). Rows objects have a Close() method. No explicit closing required.
 
+	//Prepared Queries
+	// If you will be using the same query over and over you should just prepare the query.
+	// $N is the postgres query param which SQLite can use too ? is mysql's
+
+	//Under the hood, db.Query() actually prepares, executes, and closes a prepared statement
+	// That’s three round-trips to the database.
+	stmt, err := db.Prepare("SELECT * FROM todos WHERE id = $N")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	//This prepared statement *sql.Stmt is tied to the database connection from which it was created, and it holds onto that connection until you call stmt.Close()
+	defer stmt.Close()
+
 }