vb.net 2d barcode dll Exercises in Java

Encode Data Matrix 2d barcode in Java Exercises

You can do the following exercises to practice using the object-relational techniques covered in this chapter. The answers are in Appendix B. 1. The SALGRADES table has two columns to indicate salary ranges: LOWERLIMIT and UPPERLIMIT. Define your own SALRANGE_T type, based on a varray of two NUMBER(6,2) values, and use it to create an alternative SALGRADES2 table. Fill the new SALGRADES2 table with a single INSERT statement, using the existing SALGRADES table.

Create a table TESTNEST with two columns: column X and column MX. Column X is NUMBER(1,0) with values 2, 3, 4, ..., 9. Column MX is a nested table, based on a MX_TAB_T type, containing all multiples of X less than or equal to 20. Use multiset operators to solve the following problems, using the TESTNEST table you created and populated in the previous exercise: a. b. c. Which rows have a nested table containing value 12 Which nested tables are not a subset of any other subset Which nested tables have more than 42 different nonempty subsets

This appendix offers an overview of the seven case tables used throughout this book, in various formats. Its main purpose is to help you in writing SQL commands and checking your results. The first section shows an Entity Relationship Modeling (ERM) diagram, indicating the entities of the underlying data model, including their unique identifiers and their relationships. Then you can find descriptions of the seven case tables, with names and datatypes of all their columns and short explanations, when necessary. The next section shows a table diagram, focusing on all primary key and foreign key constraints. This diagram may be especially helpful when you are writing joins. The biggest component of this appendix (with the highest level of detail) is a complete listing of the seven case tables with all their rows. This overview may be useful to check your query results for correctness. At the end of this appendix, you will find two alternative representations of the case table data, showing the table rows in a compact format. The first diagram shows an overview of the 14 employees. It clearly shows the department populations and the hierarchical (manager/subordinate) relationships. The second illustration shows a matrix overview of all course offerings, with starting dates, locations, attendees (A), and trainers (T). Again, these representations may be useful to check your query results for correctness.

The ERM diagram, shown in Figure A-1, shows the seven entities (the rounded-corner boxes) with their unique identifiers and their mutual relationships. The ten crow s feet indicate one-to-many relationships. The diagram shows two types of one-tomany relationships: three relationships are completely optional (indicated by all dashed lines) and the remaining ones are mandatory in one direction (indicated by the solid part of the line). Hash signs (#) in front of an attribute mean that the attribute is part of the unique identifier; relationship cross-lines indicate that the relationship is part of the unique identifier. Note that the diagram shows only attributes that are part of unique identifiers, for enhanced readability.

Figure A-1. ERM diagram of the case entities You can interpret the relationships in this diagram as follows: Every employee has at most one manager (and employees may have multiple subordinates). Every employee belongs to precisely one salary grade and is employed by at most one department (employees without a department are allowed). Each department has precisely one manager (and employees may be manager of multiple departments). Each course offering refers to precisely one existing course, with at most one employee as trainer. Each registration is for precisely one employee and for precisely one course offering. Each history record refers to precisely one employee and precisely one department.