tailieunhanh - Beginning Database Design- P18

Beginning Database Design- P18:This book focuses on the relational database model from a beginning perspective. The title is, therefore, Beginning Database Design. A database is a repository for data. In other words, you can store lots of information in a database. A relational database is a special type of database using structures called tables. Tables are linked together using what are called relationships. You can build tables with relationships between those tables, not only to organize your data, but also to allow later retrieval of information from the database | Seller_Nulls sellerjd FK I- return_policy international Seller Payment Methods seller_id FK payment_method 4 Seller_Name sellerjd FK name Region regionjd region I--- Seller Address sellerjd FK Seller address sellerjd popularity_rating join_date Category Primary Country countryjd regionjd FK country 4 Location locationjd regionjd FK State statejd FK cityjd FK statejd countryjd FK -j state _ . . primaryjd primary Category Secondary secondaryjd primaryjd FK secondary Category .Tertiary tertiaryjd secondaryjd FK tertiary Buyer_Name buyerjd FK name History factjd tertiaryjd FK secondaryjd FK locationjd FK timejd FK buyerJd FK sellerjd FK history_buyer history_buyer_comment_date history_seller history_seller_comment_date history_seller_comments Figure 10-36 A data warehouse history fact table snowflake schema a history data mart . Buyer buyerjd Buyer_Address popula rity_rati ng join_date H buyerjd FK address Time timejd e yearjd FK quarterjd FK monthjd FK Year yearjd year Quarter quarterjd yearjd FK quarter Month monthjd - - quarterjd FK month Chapter 10 Merchandise Discography discography_id band_id FK cd_name release_date price Figure 10-37 Musicians bands their online advertisements and some other goodies. How It Works Figure 10-37 shows the analyzed data warehouse database model for online musician and band advertisements. The most significant requirement is to ultimately produce a single star schema if a single star schema is possible. Also add any dimensional and fact information shown as additional in Figure 10-32. Figure 10-37 shows that the SHOW table is actually fact information not dimensional. Examine Figure 10-37 once more. Think about the records in the tables. Yes many advertisements are possible. However a simple search of the Internet on Web sites such as and will reveal to you the sheer volume of advertisements musicians bands shows discography released CDs and venues. Figure 10-38 takes another slant on this data .