framework/db/mysql/ColumnSchema.php
public function dbTypecast($value)
    {
        if ($value === null) {
            return $value;
        }

        if ($value instanceof ExpressionInterface) {
            return $value;
        }

        if (!$this->disableJsonSupport && $this->dbType === Schema::TYPE_JSON) {
            return new JsonExpression($value, $this->type);
        }

        return $this->typecast($value);
    }
public function dbTypecast($value)
    {
        if ($value === null) {
            return $value;
        }

        if ($value instanceof ExpressionInterface) {
            return $value;
        }

        if (!$this->disableJsonSupport && $this->dbType === Schema::TYPE_JSON) {
            return new JsonExpression($value, $this->type);
        }

        return $this->typecast($value);
    }
{@inheritdoc}