free barcode generator using vb.net UPDATING DATA in Software

Painting Code 128A in Software UPDATING DATA

UPDATING DATA
Scan USS Code 128 In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Code 128 Creator In None
Using Barcode drawer for Software Control to generate, create Code 128 Code Set A image in Software applications.
Figure 10-6.
Code-128 Decoder In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
Generate Code 128C In C#.NET
Using Barcode encoder for .NET Control to generate, create ANSI/AIM Code 128 image in VS .NET applications.
UPDATE statement syntax diagram
Code 128C Generator In VS .NET
Using Barcode creator for ASP.NET Control to generate, create Code 128 Code Set A image in ASP.NET applications.
Code 128 Code Set C Drawer In Visual Studio .NET
Using Barcode generator for Visual Studio .NET Control to generate, create Code 128 Code Set B image in VS .NET applications.
SQL: The Complete Reference
Painting Code 128 Code Set A In Visual Basic .NET
Using Barcode creation for .NET framework Control to generate, create Code 128A image in Visual Studio .NET applications.
Encoding Bar Code In None
Using Barcode drawer for Software Control to generate, create barcode image in Software applications.
In this example, the WHERE clause identifies a single row of the CUSTOMERS table, and the SET clause assigns new values to two of the columns in that row. The WHERE clause is exactly the same one you would use in a DELETE or SELECT statement to identify the row. In fact, the search conditions that can appear in the WHERE clause of an UPDATE statement are exactly the same as those available in the SELECT and DELETE statements. Like the DELETE statement, the UPDATE statement can update several rows at once with the proper search condition, as in this example: Transfer all salespeople from the Chicago office (number 12) to the New York office (number 11), and lower their quotas by 10 percent.
EAN-13 Supplement 5 Printer In None
Using Barcode creation for Software Control to generate, create GTIN - 13 image in Software applications.
Code 128B Creator In None
Using Barcode creator for Software Control to generate, create Code 128 Code Set C image in Software applications.
UPDATE SALESREPS SET REP_OFFICE = 11, QUOTA = .9 * QUOTA WHERE REP_OFFICE = 12 3 rows updated.
Data Matrix 2d Barcode Generator In None
Using Barcode creator for Software Control to generate, create DataMatrix image in Software applications.
UPCA Generation In None
Using Barcode creation for Software Control to generate, create Universal Product Code version A image in Software applications.
In this case, the WHERE clause selects several rows of the SALESREPS table, and the value of the REP_OFFICE and QUOTA columns are modified in all of them. Conceptually, SQL processes the UPDATE statement by going through the SALESREPS table row by row, updating those rows for which the search condition yields a TRUE result and skipping over those for which the search condition yields a FALSE or NULL result. Because it searches the table, this form of the UPDATE statement is sometimes called a searched UPDATE statement. This term distinguishes it from a different form of the UPDATE statement, called a positioned UPDATE statement, which always updates a single row. The positioned UPDATE statement applies only to programmatic SQL and is described in 17. Here are some additional examples of searched UPDATE statements: Reassign all customers served by employee numbers 105, 106, or 107 to employee number 102.
USPS POSTNET Barcode Encoder In None
Using Barcode printer for Software Control to generate, create Delivery Point Barcode (DPBC) image in Software applications.
DataMatrix Encoder In Visual Studio .NET
Using Barcode printer for ASP.NET Control to generate, create Data Matrix image in ASP.NET applications.
UPDATE CUSTOMERS SET CUST_REP = 102 WHERE CUST_REP IN (105, 106, 107) 5 rows updated.
Encoding Barcode In None
Using Barcode creator for Word Control to generate, create barcode image in Microsoft Word applications.
Barcode Generator In Java
Using Barcode creation for Android Control to generate, create bar code image in Android applications.
Assign a quota of $100,000 to any salesperson who currently has no quota.
Making Code-39 In Objective-C
Using Barcode drawer for iPhone Control to generate, create Code 3 of 9 image in iPhone applications.
Scanning DataMatrix In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
UPDATE SALESREPS SET QUOTA = 100000.00
Scan Data Matrix ECC200 In Visual Basic .NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
Creating EAN 13 In None
Using Barcode maker for Online Control to generate, create EAN-13 Supplement 5 image in Online applications.
10:
Database Updates
WHERE QUOTA IS NULL 1 row updated.
The SET clause in the UPDATE statement is a list of assignments separated by commas. Each assignment identifies a target column to be updated and specifies how to calculate the new value for the target column. Each target column should appear only once in the list; there should not be two assignments for the same target column. The ANSI/ISO specification mandates unqualified names for the target columns, but some SQL implementations allow qualified column names. There can be no ambiguity in the column names anyway, because they must refer to columns of the target table. The expression in each assignment can be any valid SQL expression that yields a value of the appropriate data type for the target column. The expression must be computable based on the values of the row currently being updated in the target table. In most DBMS implementations, the expression may not include any column functions or subqueries. If an expression in the assignment list references one of the columns of the target table, the value used to calculate the expression is the value of that column in the current row before any updates are applied. The same is true of column references that occur in the WHERE clause. For example, consider this (somewhat contrived) UPDATE statement:
UPDATE OFFICES SET QUOTA = 400000.00, SALES = QUOTA WHERE QUOTA < 400000.00
UPDATING DATA
Before the update, Bill Adams had a QUOTA value of $350,000 and a SALES value of $367,911. After the update, his row has a SALES value of $350,000, not $400,000. The order of the assignments in the SET clause is thus immaterial; the assignments can be specified in any order.
Updating All Rows
The WHERE clause in the UPDATE statement is optional. If the WHERE clause is omitted, then all rows of the target table are updated, as in this example: Raise all quotas by 5 percent.
UPDATE SALESREPS SET QUOTA = 1.05 * QUOTA 10 rows updated.
SQL: The Complete Reference
Unlike the DELETE statement, in which the WHERE clause is almost never omitted, the UPDATE statement without a WHERE clause performs a useful function. It basically performs a bulk update of the entire table, as demonstrated in the preceding example.
UPDATE with Subquery *
As with the DELETE statement, subqueries can play an important role in the UPDATE statement because they let you select rows to update based on information contained in other tables. Here are several examples of UPDATE statements that use subqueries: Raise by $5000 the credit limit of any customer who has placed an order for more than $25,000.
UPDATE CUSTOMERS SET CREDIT_LIMIT = CREDIT_LIMIT + 5000.00 WHERE CUST_NUM IN (SELECT DISTINCT CUST FROM ORDERS WHERE AMOUNT > 25000.00) 4 rows updated.
Copyright © OnBarcode.com . All rights reserved.