HUsing ADO.NET 2.0 with Microsoft Access Databases - Cengage ...

More documents

Recommendations

Info

20 Appendix H Using ADO.NET 2.0 with Microsoft Access Databases The SQL syntax, which refers to the rules you must follow to use the language, was accepted by the American National Standards Institute (ANSI) in 1986. You can use SQL in many database management systems and programming languages. Morgan Industries application contains one query. The query is associated with two methods named Fill and GetData. As you learned earlier, the Fill method populates an existing table with data, and the GetData method creates a new table and populates it with data. You can view the information contained in a query by right-clicking the query in the DataSet Designer window, and then clicking Configure. Doing this opens the TableAdapter Configuration Wizard, as shown in Figure H.26. SQL SELECT statement SQL also can be pronounced like the word sequel. FIGURE H.26 TableAdapter Configuration Wizard Queries are created using a special language called Structured Query Language or, more simply, SQL. SQL, which is pronounced ess-cue-el, is a set of commands that allows you to access and manipulate the data stored in many database management systems on computers of all sizes, from large mainframes to small microcomputers. You can use SQL commands to perform database tasks such as storing, retrieving, updating, deleting, and sorting data. The SELECT statement, which appears in Figure H.26, is the most commonly used command in SQL. The SELECT statement allows you to specify the fields and records you want to view, as well as control the order in which the fields and records appear when displayed. Figure H.27 shows the basic syntax of the SELECT statement and includes several examples of using the statement to access the data stored in the Employees database (shown earlier in Figure H.3). As you may remember, the database contains one table (named tblEmploy) and seven fields. The Emp_Number, Rate, and Code fields contain numeric data. The Last_Name, First_Name, and Hired fields contain text data, and the Status field contains one character. Appendix H C5779 39147 Page 20 07/10/06--JHR
Dataset Designer 21 Appendix H C5779 39147 Page 21 07/10/06--JHR HOW TO… Use the SELECT Statement Syntax SELECT fields FROM table [WHERE condition] [ORDER BY field] Example 1 SELECT Emp_Number, Last_Name, First_Name, Hired, Rate, Status, Code FROM tblEmploy selects all of the fields and records in the table Example 2 SELECT Emp_Number, First_Name, Last_Name FROM tblEmploy selects the Emp_Number, First_Name, and Last_Name fields from each record in the table Example 3 SELECT Emp_Number, Last_Name, First_Name, Hired, Rate, Status, Code FROM tblEmploy WHERE Status = 'F' selects the records for full-time employees Example 4 SELECT Emp_Number, Rate FROM tblEmploy WHERE Code = 3 selects the Emp_Number and Rate fields for employees in the Personnel department Example 5 SELECT Emp_Number FROM tblEmploy WHERE Last_Name LIKE 'Smith' selects the Emp_Number field for records that have a last name of Smith Example 6 SELECT Emp_Number FROM tblEmploy WHERE Last_Name LIKE 'S%' selects the Emp_Number field for records whose last name begins with the letter S Example 7 SELECT Emp_Number, Last_Name, First_Name, Hired, Rate, Status, Code FROM tblEmploy ORDER BY Code selects all of the fields and records in the table, and sorts the records in ascending order by the Code field Example 8 SELECT Emp_Number, Last_Name, First_Name, Hired, Rate, Status, Code FROM tblEmploy WHERE Status = 'p' ORDER BY Code selects the records for part-time employees, and sorts the records in ascending order by the Code field FIGURE H.27 How to use the SELECT statement The full syntax of the Select statement contains other clauses and options that are beyond the scope of this book. In the SELECT statement’s syntax, fields is one or more field names (separated by commas), and table is the name of the table containing the fields. Notice that the SELECT statement’s syntax contains two clauses that are optional: the WHERE clause and the ORDER BY clause. The WHERE clause allows you to limit the records that will be selected, and the ORDER BY clause allows you to control the order in which the records appear when displayed. Although
Page 1 and 2: H Using ADO.NET 2.0 with Microsoft
Page 3 and 4: Database Terminology 3 Notice that
Page 5 and 6: Connecting a Database to an Applica
Page 7 and 8: Connecting a Database to an Applica
Page 9 and 10: Binding the Objects in a Dataset 9
Page 17 and 18: Accessing the Records in a Dataset
Page 19: Dataset Designer 19 You can use the
Page 23 and 24: Dataset Designer 23 3. In the Choos
Page 25 and 26: Dataset Designer 25 Used by the WHE
Page 27 and 28: Dataset Designer 27 The user can ru
Page 29 and 30: Programming Tutorial 29 TOE Chart:
Page 31 and 32: Programming Tutorial 31 6. Click th
Page 33 and 34: Programming Tutorial 33 Appendix H
Page 35 and 36: Programming Tutorial 35 5. Click th
Page 37 and 38: Programming Tutorial 37 Option Expl
Page 39 and 40: Programming Example 39 TOE Chart: T
Page 41 and 42: Quick Review 41 Private Sub MainFor
Page 43 and 44: Self-Check Questions and Answers 43
Page 45 and 46: Review Questions 45 3. A group of r
Page 47 and 48: Computer Exercises 47 3. Write a SE
Page 49 and 50: Case Projects 49 c. Allow the user

HUsing ADO.NET 2.0 with Microsoft Access Databases - Cengage ...

Create successful ePaper yourself

Delete template?

Save as template?