لینک دانلود پاورپیونت Network Model - پنجاه و نه اسلاید

        n Data are represented by collections of records . l similar to an entity in the E-R model l Records and their fields are represented as record type type  customer = record  type  account = record   customer-name: string;  account-number: integer;   customer-street: string;  balance: integer;   customer-city: string; end  end n Relationships among data are represented by links l similar to a restricted (binary) form of an E-R relationship l restrictions on links depend on whether the relationship is many-many, many-to-one, or one-to-one. برای دانلود کل پاورپوینت از لینک زیر استفاده کنید: ...

دانلود پاورپیونت Network Model پنجاه و نه اسلاید برای پشتیبانی و خرید فایل به سایت فروشنده مراجعه بفرمائید

لینک دانلود پاورپوینت Hierarchical Model - پنجاه و هشت اسلاید

        n A hierarchical database consists of a collection of records which are connected to one another through links. n a record is a collection of fields, each of which contains only one data value. n A link is an association between precisely two records. n The hierarchical model differs from the network model in that the records are organized as collections of trees rather than as arbitrary graphs. برای دانلود کل پاورپوینت از لینک زیر استفاده کنید: ...

دانلود پاورپوینت Hierarchical Model پنجاه و هشت اسلاید برای پشتیبانی و خرید فایل به سایت فروشنده مراجعه بفرمائید