删除数据库内容后，MS Access（.mdb）文件大小是否会减少？

I was inserting data into a MS Access database using JDBC-ODBC driver. The blank mdb file was 2KB. After populating this database, the size grew to 155MB. Then I was deleting the data. But I found the size of mdb remains the same as 155MB. I don't get any errors. But is it normal this way? I would expect the file size reduces. If it is designed in this way, what is the idea behind it? ThanksI was inserting data into a MS Access database