Separate exec types into files, document code (#10)

Reviewed-on: #10

exec/update.go

@@ -0,0 +1,85 @@
+package exec
+
+import (
+	"database/sql"
+	"errors"
+	"reflect"
+
+	"git.gdulai.com/gdulai/simpleorm"
+	"git.gdulai.com/gdulai/simpleorm/schema"
+	log "gitlab.com/gdulai/simpleloglvl"
+)
+
+// Update represents an update operation.
+type Update[T any] struct {
+	target   schema.Table // The table where records will be updated.
+	toUpdate T            // A model instance with the new values.
+}
+
+// NewUpdate creates a new instance of Update.
+//
+// Parameters:
+// - orm: The ORM instance that manages the database connection and schema
+// - toUpdate: A model instance with new values
+//
+// Returns:
+// - Update[T]: A new Update operation instance
+// - error: An error if the table could not be found in the schema cache
+func NewUpdate[T any](orm *simpleorm.ORM, toUpdate T) (Update[T], error) {
+	table, ok := orm.Cache().Get(reflect.TypeFor[T]().Name())
+	if !ok {
+		return Update[T]{}, errors.New("Failed to get table from schema cache")
+	}
+
+	return Update[T]{target: *table, toUpdate: toUpdate}, nil
+}
+
+// Execute executes the update operation.
+func (u Update[T]) Execute(conn *simpleorm.DBConnection) error {
+	return u.execute(conn, nil)
+}
+
+// execute constructs and executes the UPDATE SQL statement.
+//
+// Parameters:
+// - conn: The database connection to use for executing the query
+// - tx: Optional transaction to use instead of a connection
+//
+// Returns:
+// - error: An error if the operation fails
+func (u Update[T]) execute(conn *simpleorm.DBConnection, tx *sql.Tx) error {
+	dml, err := u.target.GetUpdateDML()
+	if err != nil {
+		return err
+	}
+
+	params := prepareParams(u.toUpdate, u.target)
+
+	pkCols, err := getPk(u.toUpdate, u.target)
+	if err != nil {
+		return err
+	}
+	// Put the pks back at the end
+	for _, pk := range pkCols {
+		params = append(params, pk)
+	}
+
+	log.LogDebug("%s [%s]", dml, params)
+
+	var stmt *sql.Stmt
+	if tx != nil {
+		stmt, err = tx.Prepare(dml)
+	} else {
+		stmt, err = conn.Prepare(dml)
+	}
+	defer stmt.Close()
+
+	result, err := stmt.Exec(params...)
+	if err != nil {
+		return err
+	} else {
+		rowsAffected, _ := result.RowsAffected()
+		log.LogInfo("Updated %s row", rowsAffected)
+	}
+	return nil
+}