Tutorials,Articles,Algorithms,Tips,Examples about Database

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SQL Server 2008 R2 : Database Maintenance - Executing a Maintenance Plan

Maintenance plans that have been scheduled run automatically according to the schedule defined. You can also run maintenance plans manually by right-clicking a maintenance plan and selecting Execute or by selecting the SQL Server Agent job associated with the maintenance plan and starting the job.

SQL Server 2008 R2 : Database Maintenance - Managing Maintenance Plans Without the Wizard

You can create or modify maintenance plans in SQL Server 2008 without using the Maintenance Plan Wizard. To create a new maintenance plan without the wizard, you right-click the Maintenance Plan node in the Object Explorer and select New Maintenance Plan

SQL Server 2008 R2 : The Maintenance Plan Wizard (part 2)

Maintaining indexes and statistics is essential in most database environments, including those that have frequent changes to the data. These changes can cause tables and their indexes to become fragmented and inefficient.

SQL Server 2008 R2 : The Maintenance Plan Wizard (part 1)

The Maintenance Plan Wizard is a tool that is available in SSMS. It provides an automated means for creating the basic tasks needed to maintain a database. It does not include all the tasks available for use in a maintenance plan but is a great starting point that allows you to quickly generate the basic elements of a good plan.

SQL Server 2008 : Common performance problems (part 2)

The correct selection and maintenance of indexes are crucial from a query-performance perspective. Numerous unused indexes have a large maintenance overhead, and missing or poorly maintained indexes have a double impact on resources: additional disk I/O and a reduction in the available buffer cache.

SQL Server 2008 : Common performance problems (part 1) - Procedure cache bloating

Each time a query is submitted for processing, SQL Server assesses the contents of the procedure cache for an existing plan that can be reused. If none is found, SQL Server generates a new plan, storing it in the procedure cache for (possible) later reuse.

SQL Server 2008 : SQLOS schedulers, Wait analysis

SQL Server is a large and complex product with many interconnected components requiring access to common services such as memory allocation and process scheduling. In order to reduce the complexity of each of these components, the SQL Server architecture includes a layer responsible for providing common services.

MySQL for Python : Creating Users and Granting Access - Removing privileges in MySQL, Using REVOKE in Python

All administrative changes in MySQL are applied to MySQL's internal databases. Therefore, any change that is effected, only takes effect the next time MySQL needs to read those administrative tables. Consequently, users can still have access to databases or tables after the revocation statement has been issued.

MySQL for Python : Creating Users and Granting Access - GRANT access in MySQL

After creating a user account, one still needs to tell MySQL what kind of privileges to assign to it. MySQL supports a wide range of privileges (see the table of privileges on page 9). A user can only grant any privilege that they have themselves.

MySQL for Python : Creating Users and Granting Access - Removing users in MySQL, DROPping users in Python, Granting access in Python

As with creating databases and tables, the opposite of creating a user is to DROP. As we shall see, removing a user does not revert any changes that they have made to the database(s) to which they had access. If a user had the ability to create users, removing them will not remove the users they created.

MySQL for Python : Creating Users and Granting Access - Creating users from Python

The ability to create users is obviously an administrative task. By default, this means that one must log in as root, or any other user who has administrative rights, to use them. If your Python program does not login as root, it will not be able to affect user creation.

MySQL for Python : Creating Users and Granting Access - Creating users in MySQL

To create a user in MySQL, our user account must have the universal CREATE USER privilege. In general, no user beyond the database administrator should have this as it allows the user to create, remove, rename, and revoke the privileges of users on the database.

Intel SSD 335 Series - Better Under The Hood

With the prices of SSDs gradually and steadily coming down, they are quickly becoming must-have items for anyone looking for a faster and more responsive computer whether desktop or laptop. Intel is regarded as one of the top names in the SSD market, thanks to its production of drives that are among the fastest in the world.

WD Black 4TB - 4TB Storage Goes Mainstream

Hot on the heels of the enterprise-class RE SATA 4TB (WD4000FYYZ) hard drive’s release, WD came out with another 4TB HDD offering. November last year saw the launch of the WD Black 4TB (WD4001FAEX) which is targeted at non-enterprise users.

Reusing T-SQL Code - Reusing Business Logic: Stored Procedure, Trigger, Constraint or Index?

Besides, unless you can guarantee that no applications can run modifications directly against the Teams table, it's likely that your business rule will be bypassed at some point, and inconsistent data will be introduced.

Reusing T-SQL Code - Scalar UDFs and Performance

The examples so far have demonstrated that laying out code in simple reusable modules can simplify maintenance, and reduce the chance of bugs when requirements change.

Reusing T-SQL Code - Reusing Parameterized Queries: Stored Procedures versus Inline UDFs

If we want to reuse parameterized queries, it is usually preferable to wrap them in user-defined functions. It is typically less convenient to reuse parameterized queries that are wrapped in stored procedures, as the following examples will demonstrate.

Acoustic Energy 301 Loudspeaker - Metal Master (Part 1)

Just over twenty years ago, Acoustic Energy launched its original AE-1 loudspeaker to considerable acclaim. It quickly earned a reputation as one of the best compact near-field monitors you could buy, establishing the credentials of the brand. The AE-1 continues to this day as the AE-1 Classic, but for those with less to spend AE offer their 3 Series.

SQL Server 2008 : Index design and maintenance - Managing statistics

The default statistics configuration enables SQL Server to automatically create and update statistics on all indexed columns. This setting reduces maintenance requirements and ensures SQL Server makes accurate decisions when creating query execution plans.

SQL Server 2008 : Index maintenance

The maintenance actions outlined in this section are directly associated with the corresponding analysis activities from the previous section. We'll begin with dropping unused or duplicated indexes before looking at removing index fragmentation.

Boot Drive Migration

You should also remember that your system will be out of commission for some time and this isn’t a quick process – if you’re lucky, and it all runs without a hitch, it can take less than an hour, but if there are issues or errors this can quickly extend to five hours or more, so it’s not something to try when you’re in a rush.

WD My Passport Edge 500GB – The Smallest One Yet

The portable hard disk drive has evolved tremendously over the last few years. From a device that needs another power source to becoming one that just simply plugs in via USB port. For better or worse, they all come in so many shapes and sizes. And oft late, in a variety of colors too.

OCZ Vector 512GB - Jumbo-capacity SSDs

Jumbo-capacity SSDs, at some level, have never quite been able to shake the niche label. When SSDs first became a realistic option for power users, the cost per gigabyte of even MLC NAND was still high enough that drives over 200GB were a pricey proposition.

Corsair Force Series GS 240GB - Blessed With Toggle-Mode NAND

This attractive, midrange, consumer SSD is blessed with Toggle-Mode NAND, a strain of double data rate MLC flash memory originally developed by Toshiba. Toggle NAND, as Corsair well knows, has become a favorite among SSD shoppers looking for top performance.

SQL Server : Reusing T-SQL Code - How Reusing Code Improves its Robustness

Note that the new implementation of SalesForMonth is simpler than the previous one): instead of using the CROSS APPLY clause to utilize the inline UDF, we can just invoke the scalar UDF directly in the WHERE clause.

SQL Server : Reusing T-SQL Code - The Dangers of Copy-and-Paste

The biggest problem with copy-and-paste as a means of solving a set of similar problems is that, of course, it leads to code duplication. In turn, this means that we need to maintain multiples copies of essentially the same code, but with each copy subtly modified to suit a particular need.

SQL Server 2005 Native XML Web Services : Example Native XML Web Services Project (part 3) - Creating the Client Application

For the client portion of our example, we created a simple Windows Forms application, called AdventureSales, that calls the Native XML Web Service endpoint we created and provides the user interface for searching and viewing data related to the Adventure Works Cycles customer stores.

SQL Server 2005 Native XML Web Services : Example Native XML Web Services Project (part 2) - Exposing the Endpoints

To allow our client to make ad hoc SQL queries against the database (to support the searching functionality), we set the BATCHES option to ENABLED. Because we know that the client is a Windows Forms application using the .NET Framework 2.0, we used the default WSDL option.

SQL Server 2005 Native XML Web Services : Example Native XML Web Services Project (part 1) - Creating the SQL Server Functionality

To demonstrate returning data as XML and consuming it on the client side, the first stored procedure, GetStoreInfo, shown in Listing 1, takes a store CustomerID and returns the store name and address as XML.

SQL Server 2005 Native XML Web Services : Exposing SQL Programmability as Web Services (part 2) - Calling Native XML Web Service Endpoints from Client Applications

Because Native XML Web Services fully supports SOAP 1.1 and SOAP 1.2 and returns WSDL, programming against an endpoint is pretty much the same as programming against any Web service.

SQL Server 2005 Native XML Web Services : Exposing SQL Programmability as Web Services (part 1)

Native XML Web Services provides two types of Web services access to data: exposing specific stored procedures or user-defined functions (UDFs) as Web methods, and batch mode access.

Western Digital Black 4TB Hard Drive - 4TB Storage Goes Mainstream

Hot on the heels of the enterprise-class ReSATA 4TB (WD4000FYYZ) hard drive’s release, WD came out with another 4TB HDD offering. November last year saw the launch of the WD Black 4TB (WD4001FAex) which is targeted at non-enterprise users. Like the ReSATA 4TB, the Black 4TB is a 3.5-inch internal hard drive that makes use of the current SATA 6Gbps interface and has a standard rotational speed of 7200RPM.

Intel Solid State Drive 335 Series - Better Under The Hood

HDD, SSD and Hybrid Hard Drive Competition

The capacity of the hard disk drive (HDD) is getting bigger and bigger, solid state drive (SSD) are becoming popular while hybrid hard drive combining the strength of HDD and SSD also promises to have a future which is not less attractive.

SQL Server 2008 : Index analysis (part 3) - Identifying index fragmentation

Indexes, like any other storage object, become fragmented over time through the course of normal insert, delete, and update activity. Identifying the level of fragmentation is a crucial component of a targeted maintenance plan.

SQL Server 2008 : Index analysis (part 2) - Identifying indexes to add

The analysis and potential removal of duplicate, unused, or infrequently used indexes can be periodically scheduled as a weekly or monthly maintenance task. In contrast, the addition of indexes is usually the result of a performance-tuning exercise, often started to investigate the sudden or gradual performance decline in one or more queries.

SQL Server 2008 : Index analysis (part 1) - Identifying indexes to drop/disable

Indexes that are either not used or used infrequently not only consume additional space, but they also lengthen maintenance routines and slow performance, given the need to keep them updated in line with the base table data.

ADO.NET Programming : Microsoft SQL Server CE (part 5) - Querying Schema Information

The database engines all did this differently, mainly because their internal storage mechanisms for holding this information varied from engine to engine. To improve cross-engine compatibility, the ANSI Standards Committee introduced a standard syntax for querying schema information, known as the INFORMATION_SCHEMA views.

ADO.NET Programming : Microsoft SQL Server CE (part 4) - Updating a SQL Server CE Database, The SqlCeDataAdapter Class

Just as the SqlCeCommand class has a property that holds the SqlCeConnection object to be used, the SqlCeDataAdapter class has a SelectCommand property that holds the SqlCeCommand object to be used to retrieve the data.

ADO.NET Programming : Microsoft SQL Server CE (part 3) - Retrieving and Displaying Data

Now that we have populated our SQL Server CE database with some data, we’ll look at how to display that data to the user. We start with the two-tier approach, which uses the SqlCeDataReader class, and then move on to the three-tiered approach based on the DataSet class.