... employee for all projects he or she works on is 56 hrs per week” • A constraint specification language may have to be used to express these • SQL- 99 allows triggers and ASSERTIONS to express ... Faculty of Science and Technology Database Fundamentals 44 ER-to-Relational Mapping Algorithm (6) • Step 6: Mapping of Multivalued attributes For each multivalued attribute A, create a new relatio...
... ô có liệu cần thêm vào đồ thị, tiêu đề Nhấn Copy Chọn đồ thị Để Microsoft Excel tự đa liệu vào đồ thị, nhấn Paste Để định cách vẽ đồ thị, chọn Paste Special Edit menu, chọn tuỳ chọn Thêm liệu ... với đồ thị 3-D, chọn mục bạn cần từ Apply To group Nhấn OK hai lần để quay lại bảng tính Lª ViÖt Anh – S−u tÇm vμ biªn so¹n 9/11 Giáo trình Microsoft Excel 2000 6.4 Bà...
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... Outlines SQL Server 20 08 Install guide Using T -SQL Faculty of Science and Technology Database Fundamentals SQL Server 20 05 Microsoft SQL Server 20 05 extends the performance, ... command to exit the SQLCMD utility: Exit Faculty of Science and Technology Database Fundamentals SQL Server Management Studio Start Programs SQL Server 20 08 Server Management Studio SQL Enter Pas...
... Completeness Constraint Faculty of Science and Technology Database Fundamentals 42 Constraints on Specialization and Generalization (4) • Disjointness Constraint: Specifies that the subclasses of the specialization ... Shown in EER diagrams by a single line Faculty of Science and Technology Database Fundamentals 44 Specialization/Generalization Hierarchies, Lattices & Shared Subclasses • A...
... number of tuples in the input relation R Faculty of Science and Technology Database Fundamentals 10 Example of Select • σ(Dno=4 AND Salary>25000) OR (Dno=5 AND Salary> 30000)(EMPLOYEE) Faculty
... condition>S = σ (R X S) Faculty of Science and Technology Database Fundamentals 12 Binary Relational Operations: DIVISION • DIVISION Operation The division operation is applied ... Technology Database Fundamentals 32 Languages Based on Tuple Relational Calculus • The language SQL is based on tuple calculus It uses the basic block structure to express the queries in tuple ... needed in th...
... Database Fundamentals 16 NULLS In Sql Queries • SQL allows queries that check if a value is NULL (missing/not known or undefined/withheld or not applicable/not apply) • SQL uses IS or IS NOT to compare ... and AVG • Query 15: Find the maximum salary, the minimum salary, and the average salary among all employees Q15: SELECT FROM MAX(Salary), MIN(Salary), AVG(Salary) EMPLOYEE • Some SQ...
... Chapter Faculty of Science and Technology Database Fundamentals Specifying Updates in SQL • There are three SQL commands to modify the database: INSERT DELETE UPDATE Faculty of Science and Technology ... taken when the condition is satisfied Faculty of Science and Technology Database Fundamentals 17 SQL Triggers: An Example • A trigger to compare an employee’s salary to his/her superv...