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Câu lệnh truy vấn căn bản trong SQL

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Cách dùng phát biểu SELECT để chọn dữ liệu từ một bảng trong SQL.. Cách dùng BETWEEN....AND để tìm dữ liệu trong một khoảng giới hạn.. Cách tạo các cơ sở dữ liệu và các bảng, và cách xóa chúng.. SQL là một ngôn ngữ theo chuẩn ANSI để truy xuất các cơ sở dữ liệu.. SQL cho phép bạn...

Giáo trình về ngôn ngữ SQL

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a) Chỳng ta cú thể chiếu một quan hệ do một truy vấn SQL sản xuất ra lờn trờn một số thuộc tớnh của nú. Chỳng ta cú thể viết:. d) Chỳng ta cũng cú thể cho phộp một hằng như là một biểu thức trong mệnh đề SELECT.. Chỳng ta cú thể xõy dựng cỏc điều kiện bằng cỏch...

Brad’s Sure Guide to SQL Server Maintenance Plans- P1

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Maintenance Plan Wizard ...19. Maintenance Plan Designer. Core Maintenance Plan Tasks ...24. What's Outside the Scope of the Maintenance Plan Wizard and Designer? ...27. Chapter 3: Getting Started with the Maintenance Plan Wizard. Creating a Maintenance Plan ...50. Starting the Maintenance Plan Wizard ...50. Testing Your Maintenance Plan ...77

Brad’s Sure Guide to SQL Server Maintenance Plans- P2

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An Overview of the Check Database Integrity Task ...93. When and How Often to Run Integrity Checks. Configuring the Task. Creating the Job Schedule. Chapter 6: Shrink Database Task ...101. Problems with the Shrink Database Task ...102. Chapter 7: Rebuild Index Task. An Overview of the Rebuild Index Task ...104. When and How Often to Rebuild Indexes ...106. Configuring the...

Brad’s Sure Guide to SQL Server Maintenance Plans- P3

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Create the New Maintenance Plan ...243. Add the Maintenance Plan Tasks. Configure the Maintenance Plan Tasks. Save the Maintenance Plan. Test the Maintenance Plan. Modifying an Existing Maintenance Plan. Brad McGehee, currently Director of DBA Education at Red Gate Software, is a SQL Server DBA, trainer and writer with over 15 years' SQL Server experience, and over 6 years' training...

Brad’s Sure Guide to SQL Server Maintenance Plans- P4

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Goals of this Book. As I cover how to use the Maintenance Plan Wizard and Maintenance Plan Designer in this book, I have tried to keep the following goals in mind:. not only to cover the mechanics of how to use the Maintenance Plan Wizard and Maintenance Plan Designer, but also to offer practical advice on how best to maintain...

Brad’s Sure Guide to SQL Server Maintenance Plans- P5

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For example, the maintenance task that is designed to delete older backup files can only delete one file type at a time, such as BAK or TRN , and not both at the same time. Because of this, you may have to create multiple Maintenance Plans just to perform simple tasks such as this.. Maintenance Plans created with the Wizard...

Brad’s Sure Guide to SQL Server Maintenance Plans- P6

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Over time, as indexes are subjected to data modifications ( INSERT s, UPDATE s, and DELETE s), index fragmentation can occur in the form of gaps in data pages that create wasted empty space, and in a logical ordering of the data that no longer matches the physical ordering of the data.. Both forms of fragmentation are normal byproducts of...

Brad’s Sure Guide to SQL Server Maintenance Plans- P7

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Figure 2.2: The Database Mail Configuration Wizard does several different tasks.. To set up Database Mail for use by the Maintenance Wizard, select the option Set up Database Mail by performing the following tasks. If database mail has not yet been enabled for this SQL Server instance, then you will see the screen shown in Figure 2.3. Figure 2.3: Before...

Brad’s Sure Guide to SQL Server Maintenance Plans- P8

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Figure 2.6: If the SMTP settings are not set correctly, Database Mail will not work.. Figure 2.7: Although you are only setting up one account, you can see that multiple accounts can be set up if desired.. Figure 2.8: You have to specify whether a mail profile is public or private.. As shown in Figure 2.8, your Maintenance Plan profile...

Brad’s Sure Guide to SQL Server Maintenance Plans- P9

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Figure 2.11: If all went well, you will see lots of "Success". If the Configuring… screen reports success, then Database Mail has been successfully set up for your SQL Server instance – or has it? While the success statuses are great, we still don't know if Database Mail has really been set up correctly. If there was, Database Mail won't...

Brad’s Sure Guide to SQL Server Maintenance Plans- P10

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Chapter 2: Before you Create any Maintenance Plans…. Figure 2.16: Most of the options on this screen are optional.. the Maintenance Plan Wizard. Now that we have all the preliminaries out of the way, we can focus on how to create a Maintenance Plan using the Maintenance Plan Wizard. The marketing story behind the Wizard is "answer a few simple...

Brad’s Sure Guide to SQL Server Maintenance Plans- P11

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Scheduling Maintenance Tasks. The first thing we need to do is to give our Maintenance Plan a name. You and other DBAs must be able to distinguish one Maintenance Plan from another.. If you make the wrong decision now, and later change your mind about which option you want to use, you will have to delete your existing Maintenance Plan...

Brad’s Sure Guide to SQL Server Maintenance Plans- P12

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If you use this option to remove index fragmentation, then you will also need to run the Update Statistics task as part of the same Maintenance Plan. The Update Statistics task runs the sp_updatestats system stored procedure against the tables of the selected databases, updating index and column statistics. The Execute SQL Server Agent Job task allows you to select...

Brad’s Sure Guide to SQL Server Maintenance Plans- P13

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Database Selection. As you might expect, the first step when configuring most tasks is to specify the database or databases on which the maintenance task to act. Figure 3.9: The database selection drop-down box.. This option means exactly what it says. One advantage of using this option is that it covers both user and system databases and, if you add...

Brad’s Sure Guide to SQL Server Maintenance Plans- P14

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Figure 3.11: Once at least one database is selected, additional options are the screen can be configured.. The middle section of the screen in Figure 3.11 contains the configuration options for a given task. For example, Figure 3.12 shows the same portion of the screen for the Rebuild Index task.. Figure 3.12: Task-specific configuration options for the Rebuild Index task.....

Brad’s Sure Guide to SQL Server Maintenance Plans- P15

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Figure 3.16: Since I am the only Operator, there are no other names to choose from.. If you want to send Maintenance Plan reports to multiple users, you will need to have set up an operator that uses a group e-mail account, in which case each e-mail will be sent to every member of the group, each time the plan...

Brad’s Sure Guide to SQL Server Maintenance Plans- P16

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While I don't recommend you make any changes, it is interesting to look at the command used to execute the SSIS package for a particular scheduled task, as shown in Figure 3.21.. Figure 3.21: This screen shows how the SSIS package will be executed for this maintenance task.. In this particular example, Subplan_1 of the Maintenance Plan is being run...