OZ, LE, T.W. Current and future trends in data base management systems. Proc. IFIP Congress 1974, North-Holland Pub. Co., Amsterdam, pp. 998-1006.  Home/Search   Document Not in Database   Summary   Related Articles

....such relationships (see ACM Transactions o Database Systems, Vol. 1, No. 1, Maxch 1976. PERSON Fig. 18. Data structure set de fined on the same record type (a) b) PERSON [ PERSON I Fig. 19. Relationship MARRIAGE (a) data structure diagram (b) entity relationship diagram Figure 19(a) [ 20]. The corresponding entity relationship diagram is shown in Figure 19(b) It is clear now that arrows in a data structure diagram do not always represent relationships of entities. Even in the case that an arrow represents a 1 :n relation ship, the arrow only represents a unidirectional ....

....corresponding entity relationship diagram is shown in Figure 19(b) It is clear now that arrows in a data structure diagram do not always represent relationships of entities. Even in the case that an arrow represents a 1 :n relation ship, the arrow only represents a unidirectional relationship [20] (although it is possible to find the owner record from a member record) In the entity relationship model, both directions of the relationship are represented (the roles of both entities are specified) Besides the semantic ambiguity in its arrows, the network model is awkward in handling changes ....

OZ, LE, T.W. Current and future trends in data base management systems. Proc. IFIP Congress 1974, North-Holland Pub. Co., Amsterdam, pp. 998-1006.

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