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Transcript
Exploring Microsoft Access 2003 Chapter 4 Proficiency: Relational Databases, External Data, Charts, Pivot, and the Switchboard Objectives (1 of 2) • Describe one-to-many relationships • Create a one-to-many relationship • Use the Get External Data command to get data from Microsoft Office Excel • Create and modify a multiple-table select query. Objectives (2 of 2) • Use aggregate functions to create a totals query • Use Microsoft graph to create a chart based on a table or query • Use the Switchboard Manager to create and/or modify a switchboard Overview • Share data between Microsoft Office applications • Display data from two tables in one query • Total query aggregates results from groups of records to create summary information • Create Chart and Pivot • Create a user interface Multiple-Table Queries • One-to-many relationship • Primary key (PK) • Foreign key (FK) i) Consider two relation schemas R1 and R2; ii) The attributes in FK in R1 have the same domain(s) as the primary key attributes PK in R2; the attributes FK are said to reference or refer to the relation R2. • Referential integrity A value of FK in a tuple (record) t1 of the current state r(R1) either occurs as a value of PK for some tuple t2 in the current state r(R2) or is null. In the former case, we have t1[FK] = t2[PK], and we say that the tuple t1 references or refers to the tuple t2. Example: FK Employee(SSN, …, Dno) Dept(Dno, … ) Get External Data • Get External Data command • Export command • Import Spreadsheet Wizard • Import Text Wizard • Importing versus linking Importing & Exporting Hands-On Exercise 1 • Open the Investment Database • Import Spreadsheet Wizard • Create the Relationship • Print the Relationship • Add the New Data • Create & Complete the Multiple-Table Query • Export the Query and Modified Tables • View the Excel Workbook Multiple Table Query Relationship between tables Each field & table to display Total Queries A total query • • • • • Summary functions Total row Group By Count function Sum function Total Queries & Charts Hands-On Exercise 2 • • • • • • • Copy Assets Under Management Query Create a Total Query Check Your Progress Start the Chart Wizard Complete the Chart Wizard Increase the Plot Area Change the Data Total Query Run button Select Count from drop-down menu SELECT Consultants.Lastname, Count(Clients.LastName), Sum(Assets) FROM Consultants, Clients WHERE Consultant.ConsultantID = Clients.ConsultantID GROUP BY Consultants.Lastname SELECT Consultants.Lastname, Consultants.Status, Clients.Lastname, Clients.CountType, Clients.Assets FROM Consultants, Clients WHERE Consultant.ConsultantID = Clients.ConsultantID GROUP BY Consultants.Lastname 4 5 1 5 4 The results are grouped according to the last name of the consultants. The records with the same last name are in the same group. Referential Integrity Delete Record button Click + to display related records You cannot delete a Consultant without first deleting related Clients EMPLOYEE fname, minit, lname, ssn, bdate, address, sex, salary, superssn, dno DEPARTMENT Dname, dnumber, mgrssn, mgrstartdate Dnumber, dlocation DEPT _LOCATIONS PROJECT Pname, pnumber, plocation, dnum Essn, pno, hours WORKS_ON DEPENDENT Essn, dependentname, sex, bdate, relationship Updating and constraints delete •Delete the WORK_ON tuple with Essn = ‘999887777’ and pno = 10. •When deleting, the referential constraint will be checked. - The following deletion is not acceptable: Delete the EMPLOYEE tuple with ssn = ‘999887777’ - reject, cascade, modify (cascade update) Cascade delete – a strategy to enforce referential integrity Employee ssn ... 123456789 ... Works-on Essn 123456789 ... delete Pno 5 ... delete Cascade delete – a strategy to enforce referential integrity Employee ssn ... ... supervisor 234589710 123456789 ... ... 234589710 null delete Employee ssn 123456789 ... ... supervisor 234589710 ... ... 234589710 not reasonable delete null delete Modify – a strategy to enforce referential integrity Employee ssn ... 123456789 ... Works-on Essn 123456789 ... delete Pno 5 ... Works-on Essn null ... Pno 5 ... This violates the entity constraint. Modify – a strategy to enforce referential integrity Employee ssn ... 123456789 ... Department Dno ... 5 ... delete chairman 123456789 Department Dno ... 5 ... chairman null This does not violate the entity constraint. Chart Wizard View button Modified Y and X axis now match the query data Chart from Wizard The User Interface • Switchboard • Switchboard Manager • Switchboard Items table Other Access Utilities • Convert Database command • Compact and Repair Database command Compact the Database View button Select the database Click compact The Switchboard Manager Hands-On Exercise 3 • Start the Switchboard Manager • Complete the Switchboard • Test the Switchboard • Insert the Clip Art • Complete the Design • The Completed Switchboard • Compact the Database Switchboard Manager Each button corresponds to a command Chapter 4 Summary (1 of 2) • One-to-many relationships • A query can display data from multiple tables • Get External Data command • A total query performs calculations on • a group of records using summary functions Chapter 4 Summary (2 of 2) • Switchboard Manager creates the user interface (Switchboard) • Convert Database command changes an Access 2000 file to a previous version • Compact and Repair Database command Practice with Access 1. The Client Master List 2. The HMO Database 3. Creating a Switchboard 4. The Look Ahead Databas 5. Linking Versus Importing 6. Pivot Tables 7. Pivot Charts Case Studies • Your First Consultant’s Job • The Wellness Center • The Database Wizard • Compacting Versus Compressing