tailieunhanh - Using Visual Basic NET Databases to Create Pricing Trading R_5

Tham khảo tài liệu 'using visual basic net databases to create pricing trading r_5', tài chính - ngân hàng, tài chính doanh nghiệp phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Relational Databases 193 1. Define the purpose of the database and the tasks that users will perform against it. 2. Analyze current database solutions. 3. Create tables fields and primary keys that characterize the subjects the database will track. 4. Determine the relationships that exist between tables. 5. Define the constraints or business rules for the data. 6. Develop ways to look at or view the data. 7. Review the integrity of the data including checking the field specifications testing the validity of relationships and reviewing the business rules. A well-designed database is easy to modify structurally allows for efficient retrieval of data and makes it easy for developers to build applications to connect to it Hernandez 1997 p. 28 . ACCESS DATABASES MS Access databases are relational databases supported by all Microsoft Windows environments. You do not need to have MS Access software installed on your computer to interface with Access databases through . In an Access database all the various parts of the database are stored in a single file which has an .mdb extension. The CD contains three Access databases and that we will use over the course of the remainder of the book. If you have MS Access software on your computer feel free to open these databases in Access and examine their structures. Let s take a look at each of them. The Database is an MS Access database included on the CD with this book that uses flat files to hold daily historical price data for 13 stocks and the S P 500. The individual data tables in are named AXP GE GM IBM INTC JNJ KO MCD MO MRK MSFT SUNW WMT and SPX. In addition there is a validation table named Tickers which contains the 13 stock ticker symbols shown. Team-LRN 194 Database Programming The 14 data tables consist of the primary key column labeled Date and five other columns named OpenPrice HighPrice LowPrice ClosePrice and Volume. Each table .