the library entity relationship diagram
Entity Relationship Diagram
Ngày tải lên :
14/03/2013, 16:45
... thể tương ứng B theo quan hệ R1 (cardinality = [1,1]) B R1 R3 Mỗi thể A tương ứng B, không tương ứng theo quan hệ R2 (cardinality = [0,1]) B Mỗi thể A có tối đa N thể tương ứng B theo quan hệ R3 ... Khóa ngoại 36 Chương Thực thể sang bảng: 4.Weak -entity Emp_ID Dept_DOB Emp_Name Dept_Name EMPLOYEE Dept_Gender DEPENDENT “Strong entity “Weak entity EMPLOYEE Emp_ID Employee_Name DEPENDENT ... đệ quy 15 Chương ISA Entity (thực thể cha-con) 16 Cho hai tập thực thể A B Ta nói A có mối quan hệ ISA với B thực thể A thực thể B (còn gọi A B) Ký hiệu Chương ISA Entity (thực thể cha-con)...
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System Designs Entity Relationship Diagram
Ngày tải lên :
28/04/2013, 17:23
... Chức xóa khách hàng a Mục đích b Đầu vào c Các trình thực d Đầu PHẦN IV: System Designs Entity Relationship Diagram I Các kiểu thực thể Thực thể (TT) Khách hàng Mã KH Mật Họ Tên Ngàyđăng ký KHÁCH ... d Đầu - Danh sách tin Chức tìm kiếm a Mục đích - Nhằm cung cấp cho người dùng tìm kiếm sản phẩm theo ý cách nhanh b Đầu vào - Hãng sản xuất - Khối lượng - Giá c Các trình thực - Truy cập CSDL ... quy trình cần thực Cả nhóm Xây dựng sơ đồ thực thể quan hệ thiết kế bảng CSDL.Chỉnh sửa CSDL theo Thiết kế chi tiết yêu cầu của bài toán Quân Thu thập thông tin cho CSDL Nhập thông tin...
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Database Design Using Entity-Relationship Diagrams
Ngày tải lên :
22/10/2013, 10:15
... modeled using an Entity Relationship (ER) diagram as the "blueprint" from which the actual data is stored — the output of the design phase The ER diagram is an analyst's tool to diagram the data to ... first-impression entity (our primary entity) Translate the diagram into English Present the English (and the diagram) back to the user to see if we have it right and then progress from there The third ... Chapter introduces the concepts of the entity, attributes, relationships, and the "one -entity" ER diagram Steps 1, 2, and of the ER Design Methodology are developed The "one -entity" grammar and...
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Database Design Using Entity-Relationship Diagrams docx
Ngày tải lên :
27/06/2014, 08:20
... modeled using an Entity Relationship (ER) diagram as the "blueprint" from which the actual data is stored — the output of the design phase The ER diagram is an analyst's tool to diagram the data to ... first-impression entity (our primary entity) Translate the diagram into English Present the English (and the diagram) back to the user to see if we have it right and then progress from there The third ... Chapter introduces the concepts of the entity, attributes, relationships, and the "one -entity" ER diagram Steps 1, 2, and of the ER Design Methodology are developed The "one -entity" grammar and...
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Entity Relationship Diagrams ppsx
Ngày tải lên :
05/07/2014, 20:20
... • • • • • • Mandatory Relationships Optional Relationships Many-to-Many Relationships One-to-Many Relationships One-to-One Relationships Recursive Relationships Mandatory, Many-to-Many INSTRUCTOR ... Many-to-Many Relationships • Many-to-many relationships should be avoided We can resolve a many-to-many relationship by dividing it into two one-tomany relationships 11 Resolving Many-to-Many Relationships ... information within an entity. ”1 • Do we know a similar concept? 1) Stephens, R.K and Plew R.R., 2001 Database Design SAMS, Indianapolis , IN Entity Relationship Models • • • • • • Mandatory Relationships...
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Database Design Using Entity-Relationship Diagrams phần 1 doc
Ngày tải lên :
13/08/2014, 12:21
... modeled using an Entity Relationship (ER) diagram as the "blueprint" from which the actual data is stored — the output of the design phase The ER diagram is an analyst's tool to diagram the data to ... Chapter introduces the concepts of the entity, attributes, relationships, and the "one -entity" ER diagram Steps 1, 2, and of the ER Design Methodology are developed The "one -entity" grammar and ... mapping rules for the" one -entity" diagram are presented Chapter extends the one -entity diagram to include a second entity The concept of testing attributes for entities is discussed and relationships...
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Database Design Using Entity-Relationship Diagrams phần 2 pps
Ngày tải lên :
13/08/2014, 12:21
... first-impression entity (our primary entity) Translate the diagram into English Present the English (and the diagram) back to the user to see if we have it right and then progress from there The third ... the Entity Now that we have an entity with attributes, we want to prepare the first feedback to the user — the English description Users will not likely want to study the entity diagram but they ... address, the business phone number, the owner's phone number, and the first names of the employees who work at the business Draw the ER diagram using the Chen-like model, and then write the English...
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Database Design Using Entity-Relationship Diagrams phần 3 ppsx
Ngày tải lên :
13/08/2014, 12:21
... "1" on the line between the entity box for the STUDENT and the diamond box for the relationship, and we put another "1" on the line between the diamond relationship and the entity box for the AUTOMOBILE ... added the attribute, automobile, to the entity, STUDENT, and then recognized that automobile should have been an entity, we would create the AUTOMOBILE entity and then add the relationship to the ... entity, and then Step 3b: Define the relationship back to the original entity Step 4: If another entity is appropriate, draw the second entity with its attributes Repeat step to see if this entity...
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Database Design Using Entity-Relationship Diagrams phần 4 ppsx
Ngày tải lên :
13/08/2014, 12:21
... attribute is needed, then make the attribute an entity, and then Step 3b: Define the relationship back to the original entity Step 4: If another entity is appropriate, draw the second entity with its ... For binary 1:1 relationships, if one of the sides has full participation in the relationship, and the other has partial participation, then store the primary key of the side with the partial participation ... without the relationship to the other entity Pattern 3: Relationship is x:y::1(full):M Diagramatically shown by Figure 4I Figure 4I: Chen Model of 1(full):M Relationship — Pattern Pattern 3: Relationship...
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Database Design Using Entity-Relationship Diagrams phần 5 ppsx
Ngày tải lên :
13/08/2014, 12:21
... put the grade attribute with the COURSE entity, the COURSE entity would have to be related to the STUDENT entity The correct place for the grade attribute in the diagram would be on the relationship, ... of the weak relation will be the partial key in the weak entity concatenated to the key of the owner entity If weak entities own other weak entities, then the weak entity that is connected to the ... trains, etc.) The type attribute of HOBBY is a partial key for HOBBY The entity DEPENDENT is the owner of the entity HOBBY, and the entity EMPLOYEE is the owner of the weak entity DEPENDENT The reason...
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Database Design Using Entity-Relationship Diagrams phần 6 pot
Ngày tải lên :
13/08/2014, 12:21
... instructor In this diagram (Figure 6.3), the INSTRUCTOR entity is related to the COURSE entity There could be a relationship between the INSTRUCTOR entity and the STUDENT entity, but the relationships ... attribute is needed, then make the attribute an entity, and then Step 3b: Define the relationship back to the original entity Step 4: If another entity is appropriate, draw the second entity with its ... rules basically stay the same; but rather than including the primary key of one entity (ENTITY_ A) in another entity (ENTITY_ B), the primary key of ENTITY_ A is reincluded in ENTITY_ A M5 — For recursive...
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Database Design Using Entity-Relationship Diagrams phần 7 ppsx
Ngày tải lên :
13/08/2014, 12:21
... attribute is needed, make the attribute an entity, and then Step 3b: Define the relationship back to the original entity Step 4: If another entity is appropriate, draw the second entity with its attributes ... in the diagram the price of the security, the commission paid, the broker name and address, the buyer name and address, and the security exchange, symbol, and price Include in the diagram the ... all entities for the n-ary relationship State the structural constraints as they exist The grammar for the n-ary relationship must involve all of the entities linked to it and, therefore, a suitable...
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Database Design Using Entity-Relationship Diagrams phần 8 ppsx
Ngày tải lên :
13/08/2014, 12:21
... will be the partial key in the weak entity concatenated to the key of the owner entity If weak entities own other weak entities, then the weak entity that is connected to the strong entity must ... attribute is needed, make the attribute an entity, and then Step 3b: Define the relationship back to the original entity Step 4: If another entity is appropriate, draw the second entity with its attributes ... each entity in their each respective tables Add the key of the generalization entity into the specialization entity The primary key of the specialization will be the same primary key as the generalization...
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Database Design Using Entity-Relationship Diagrams phần 9 pptx
Ngày tải lên :
13/08/2014, 12:21
... of the "weak entity, " and the weak entity notation is not used in Oracle literature either We will extend the concept of the unique identifier in a relationship to include the weak entity In the ... 10.6: 1:M Relationship in the Barker/Oracle-Like Notation Checkpoint 10.2 How is the "optional" relationship shown diagrammatically in the Barker/Oracle-like model? How is the "many" relationship ... model, the multivalued attribute is kept in the diagram and then mapped using the mapping rules (see mapping rule M1c) Checkpoint 10.3 Does the Barker-like model or the Oracle-like model have the...
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Database Design Using Entity-Relationship Diagrams phần 10 docx
Ngày tải lên :
13/08/2014, 12:21
... Weak AUTOMOBILE Entity Figure 2.8: An ER Diagram of the STUDENT-AUTOMOBILE Database Figure 2.9: The MALL Entity Chapter 3: Beyond the First Entity Diagram Figure 3.1: A STUDENT Entity with a Multi-Valued ... 1:M Relationship Figure 4.5: An ER Diagram (without Attributes) of a M:1 Relationship Figure 4.6: An ER Diagram (without Attributes) of a M:N Relationship Figure 4.7: The PASSENGER Entity Diagram ... Figure 5.2: The EMPLOYEE–DEPENDENT ER Diagram — First Pass Figure 5.3: The EMPLOYEE–DEPENDENT ER Diagram Figure 5.4: A Weak Entity with Two Relationships Figure 5.5: The PERSON–PET–VET ER Diagram...
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Mô hình thực thể kết hợp ER (Entity Relationship)
Ngày tải lên :
19/09/2013, 00:31
... riêng Không thể giản đồ ER Entity, Entity Type, Entity Set Loại thực thể (entity type) Một tập hợp thực thể có thuộc tính có giá trị khác thuộc tính Tập thực thể (entity set) Một tập hợp ... quan hệ từ giản đồ ER Các ký hiệu mô hình ER … Entity Type Composite Attribute Weak Entity Type Derived Attribute Relationship Type Identifying Relationship Type E1 E2 R Total Participation of ... hợp Mối kết hợp (relationship) : liên hệ với hai hay nhiều thực thể khác mang ý nghĩa Tập mối kết hợp (relationship set): mối kết hợp có loại kết hợp Loại mối kết hợp (relationship type): thực...
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Tài liệu Chương 2.2 Mô hình thực thể liên kết mở rộng (Enhanced Entity-Relationship) . ppt
Ngày tải lên :
21/01/2014, 05:20
... constraint) cho biết quan hệ lớp cha thực thể lớp không tách rời (một thực thể thành viên nhiều lớp theo chuyên biệt hóa) Trong lược đồ EER, ràng buộc mô tả chữ o (overlap) bên vòng tròn Nhập môn...
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Tài liệu Mô hình thực thể kết hợp (EntityRelationship) ppt
Ngày tải lên :
25/01/2014, 09:20
... tượng cấu trúc CSDL Lược đồ thực thể - kết hợp (Entity- Relationship Diagram) - Tập thực thể (Entity Sets) Thuộc tính (Attributes) Mối quan hệ (Relationship) Tập thực thể Một thực thể đối tượng ... thực Tập hợp thực thể giống tạo thành tập thực thể Chú ý - - Thực thể (Entity) Đối tượng (Object) Tập thực thể (Entity set) Lớp đối tượng (Class of objects) Cấu trúc liệu Thao tác liệu Tập ... (Hang, Dieu hanh) (Vinh, Quan ly) 14 Mối quan hệ - Multiplicity Xét mối quan hệ nhị phân R (binary relationship) tập thực thể E F, tính multiplicity bao gồm - Một-Nhiều - E n Quan_hệ F Một-Một...
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Data Modeling Using the Entity - Relationship Model
Ngày tải lên :
12/05/2014, 11:55
... type – The particular entity they are related to in the identifying entity type Example: Suppose that a DEPENDENT entity is identified by the dependent’s first name and birhtdate, and the specific ... Degree, Field)} Entity Types and Key Attributes Entities with the same basic attributes are grouped or typed into an entity type For example, the EMPLOYEE entity type or the PROJECT entity type ... on the ProductX PROJECT or EMPLOYEE Franklin Wong manages the Research DEPARTMENT Relationships of the same type are grouped or typed into a relationship type For example, the WORKS_ON relationship...
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