initial commit

cmd/stripColumns/main.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"database/sql"
+	"flag"
+	"log"
+
+	_ "github.com/go-sql-driver/mysql"
+)
+
+var (
+	dbURL = flag.String("db", "julian:hi@/test", "Die URL zur Datenbank")
+	table = flag.String("table", "Teilnehmer", "Die Tabelle")
+	key   = flag.String("key", "Matrnr", "Der Tabellenschlüsselname")
+	attr  = flag.String("attr", "Nachname", "Die Spalte zum Cleanen")
+)
+
+const (
+	querySelect = "SELECT ?,? FROM ?"
+	queryUpdate = "UPDATE ? SET ?=? WHERE ?=?"
+)
+
+func main() {
+	flag.Parse()
+
+	db, err := sql.Open("mysql", *dbURL)
+	if err != nil {
+		log.Fatal("error connecting to database:", err)
+	}
+	defer db.Close()
+
+	statement, err := db.Prepare("SELECT " + *key + "," + *attr + " FROM " + *table)
+
+	if err != nil {
+		log.Fatal("error in precompiled statement:", querySelect+":", err)
+	}
+	defer statement.Close()
+
+	rows, err := statement.Query()
+
+	if err != nil {
+		log.Fatal("error executing query:", err)
+	}
+
+	context, err := db.Begin()
+	if err != nil {
+		log.Fatal("error creating context:", err)
+	}
+
+	update, err := context.Prepare("UPDATE " + *table + " SET " + *attr + "=? WHERE " + *key + "=?")
+	if err != nil {
+		log.Fatal("error in precompiled statement:", queryUpdate+":", err)
+	}
+
+	var (
+		keyBuffer    int
+		dirty, clean string
+
+		count int
+	)
+
+	for rows.Next() {
+		if err = rows.Scan(&keyBuffer, &dirty); err != nil {
+			log.Println("error while reading:", err)
+		}
+
+		clean = strip(dirty)
+		if clean != dirty {
+			if result, err := update.Exec(clean, keyBuffer); err != nil {
+				log.Fatal("error on update, change canceled:", err)
+			} else if i, err := result.RowsAffected(); err == nil && i != 1 {
+				log.Fatal("changed to many rows... aborting")
+			} else {
+				count++
+			}
+		}
+	}
+
+	log.Println("committing change,", count, "rows affected")
+	if err := context.Commit(); err != nil {
+		log.Println("could not commit changed:", err)
+	}
+}

cmd/stripColumns/strip.go

@@ -0,0 +1,15 @@
+package main
+
+func strip(str string) (output string) {
+	var (
+		start = 0
+		end   = len(str)
+	)
+	for ; start < len(str) && str[start] == ' '; start++ {
+	}
+
+	for ; end > 0 && str[end-1] == ' '; end-- {
+	}
+
+	return str[start:end]
+}