free barcode generator using vb.net Bulk Load Utilities in Software

Printing QR Code ISO/IEC18004 in Software Bulk Load Utilities

Bulk Load Utilities
Read QR Code 2d Barcode In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
QR Code Printer In None
Using Barcode creator for Software Control to generate, create QR Code JIS X 0510 image in Software applications.
Data to be inserted into a database is often downloaded from another computer system or collected from other sites and stored in a sequential file. To load the data into a table, you could write a program with a loop that reads each record of the file and uses the single-row INSERT statement to add the row to the table. However, the overhead of having the DBMS repeatedly execute single-row INSERT statements may be quite high.
Reading QR Code 2d Barcode In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
QR Code Maker In C#.NET
Using Barcode generator for .NET Control to generate, create QR-Code image in VS .NET applications.
- 202 -
QR Code Maker In .NET
Using Barcode generation for ASP.NET Control to generate, create QR Code ISO/IEC18004 image in ASP.NET applications.
Creating QR Code In .NET
Using Barcode creation for .NET framework Control to generate, create Denso QR Bar Code image in VS .NET applications.
If inserting a single row takes half of a second under a typical system load, that is probably acceptable performance for an interactive program. But that performance quickly becomes unacceptable when applied to the task of bulk loading 50,000 rows of data. In this case, loading the data would require over six hours. For this reason, all commercial DBMS products include a bulk load feature that loads data from a file into a table at high speed. The ANSI/ISO SQL standard does not address this function, and it is usually provided as a standalone utility program rather than as part of the SQL language. Each vendor's utility provides a slightly different set of features, functions, and commands.
Paint QR Code In VB.NET
Using Barcode drawer for VS .NET Control to generate, create QR Code JIS X 0510 image in VS .NET applications.
Generate Bar Code In None
Using Barcode creator for Software Control to generate, create bar code image in Software applications.
Deleting Data from the Database
Creating EAN / UCC - 13 In None
Using Barcode drawer for Software Control to generate, create EAN13 image in Software applications.
Drawing ANSI/AIM Code 128 In None
Using Barcode generation for Software Control to generate, create Code 128 Code Set A image in Software applications.
A row of data is typically deleted from a database when the entity represented by the row "disappears from the outside world." For example, in the sample database: When a customer cancels an order, the corresponding row of the ORDERS table must be deleted. When a salesperson leaves the company, the corresponding row of the SALESREPS table must be deleted. When a sales office is closed, the corresponding row of the OFFICES table must be deleted. If the salespeople in the office are terminated, their rows should be deleted from the SALESREPS table as well. If they are reassigned, their REP_OFFICE columns must be updated. In each case, the row is deleted to maintain the database as an accurate model of the real world. The smallest unit of data that can be deleted from a relational database is a single row.
Bar Code Generator In None
Using Barcode creator for Software Control to generate, create barcode image in Software applications.
Encoding ECC200 In None
Using Barcode generation for Software Control to generate, create DataMatrix image in Software applications.
The DELETE Statement
Print UPC - E1 In None
Using Barcode generation for Software Control to generate, create UPC-E Supplement 5 image in Software applications.
Bar Code Reader In Visual Studio .NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in VS .NET applications.
The DELETE statement, shown in Figure 10-5, removes selected rows of data from a single table. The FROM clause specifies the target table containing the rows. The WHERE clause specifies which rows of the table are to be deleted.
Linear Barcode Creator In Visual Basic .NET
Using Barcode drawer for .NET framework Control to generate, create 1D image in .NET framework applications.
Painting Code 128 In Java
Using Barcode generation for Java Control to generate, create Code 128 Code Set B image in Java applications.
Figure 10-5: DELETE statement syntax diagram
EAN 128 Generation In Java
Using Barcode printer for Java Control to generate, create EAN / UCC - 13 image in Java applications.
Bar Code Drawer In None
Using Barcode generator for Font Control to generate, create bar code image in Font applications.
Suppose that Henry Jacobsen, the new salesperson hired earlier in this chapter, has just decided to leave the company. Here is the DELETE statement that removes his row from the SALESREPS table: Remove Henry Jacobsen from the database. DELETE FROM SALESREPS WHERE NAME = 'Henry Jacobsen' 1 row deleted. The WHERE clause in this example identifies a single row of the SALESREPS table, which SQL removes from the table. The WHERE clause should have a familiar appearance it's exactly the same WHERE clause that you would specify in a SELECT statement to retrieve
Creating Code128 In None
Using Barcode encoder for Online Control to generate, create Code 128B image in Online applications.
Read Barcode In Visual C#.NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in VS .NET applications.
- 203 -
the same row from the table. The search conditions that can be specified in the WHERE clause of the DELETE statement are the same ones available in the WHERE clause of the SELECT statement, as described in s 6 and 9. Recall that search conditions in the WHERE clause of a SELECT statement can specify a single row or an entire set of rows, depending on the specific search condition. The same is true of the WHERE clause in a DELETE statement. Suppose, for example, that Mr. Jacobsen's customer, InterCorp (customer number 2126), has called to cancel all of their orders. Here is the delete statement that removes the orders from the ORDERS table: Remove all orders for InterCorp (customer number 2126). DELETE FROM ORDERS WHERE CUST = 2126 2 rows deleted. In this case, the WHERE clause selects several rows of the ORDERS table, and SQL removes all of the selected rows from the table. Conceptually, SQL applies the WHERE clause to each row of the ORDERS table, deleting those where the search condition yields a TRUE result and retaining those where the search condition yields a FALSE or NULL result. Because this type of DELETE statement searches through a table for the rows to be deleted, it is sometimes called a searched DELETE statement. This term is used to contrast it with another form of the DELETE statement, called the positioned DELETE statement, which always deletes a single row. The positioned DELETE statement applies only to programmatic SQL and is described in 17. Here are some additional examples of searched DELETE statements: Delete all orders placed before November 15, 1989. DELETE FROM ORDERS WHERE ORDER_DATE < '15-NOV-89' 5 rows deleted. Delete all rows for customers served by Bill Adams, Mary Jones, or Dan Roberts (employee numbers 105, 109, and 101). DELETE FROM CUSTOMERS WHERE CUST_REP IN (105, 109, 101) 7 rows deleted. Delete all salespeople hired before July 1988 who have not yet been assigned a quota. DELETE FROM SALESREPS WHERE HIRE_DATE < '01-JUL-88' AND QUOTA IS NULL 0 rows deleted.
Copyright © OnBarcode.com . All rights reserved.