tailieunhanh - Databases Demystified a self teaching guide phần 3

IBM tham gia NAA để phát triển GUAM vào cơ sở dữ liệu thương mại đầu tiên mô hình thứ bậc, được gọi là Hệ thống thông tin quản lý (IMS), phát hành vào năm 1966. Ngoài ra vào giữa những năm 1960, General Electric nội bộ phát triển cơ sở dữ liệu đầu tiên dựa trên mô hình mạng, dưới sự chỉ đạo của máy tính nổi bật nhà khoa học Charles W. Bachman, và đặt tên nó tích hợp dữ liệu Store (IDS) | Databases Demystified Once you have used Microsoft Access to open one or more database files a list of the most recently used database files will appear in a list just below the Open an Existing File option in the startup window. You may reopen a previously used database merely by clicking its filename in the list. After you have opened the database you will see a screen similar to the one shown in Figure 3-2. Figure 3-2 Microsoft Access main panel This is the main panel in Microsoft Access. In a column along the left margin with the heading Objects you can switch the type of database objects listed in the center of the panel. When you start Microsoft Access for the very first time the default selection is Tables. However from that point forward Microsoft Access will remember the last type you selected for the database and always return you to that type when you subsequently reopen the database. Briefly the types shown may be defined as follows Tables Relational tables. These hold the actual database data in rows and columns. CHAPTER 3 Forms-Based Database Queries Queries Stored database queries. These are called views in nearly all other relational databases. Forms GUI forms for data entry and or display within Microsoft Access. Reports Reports based on database queries. Pages Web pages for data entry and or display using a web browser. Macros Sets of actions that each perform a particular operation such as opening a form or printing a report. Modules Collections of Visual Basic programming language components that are stored as a unit. As with many personal computer-based databases Microsoft Access is not only a database but also a complete development environment for building and running applications. The database products that run on larger shared computer systems commonly called servers typically do not come with application-development environments. Learning to build application programs is well outside the scope of this book so we will not deal with the .