Tutorials,Articles,Algorithms,Tips,Examples about Database

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SQL Server 2005 : Extending Your Database System with Data Mining - Data Mining Applied (part 2)

Once you have designed and trained your mining models, it’s easy to display the results in a Reporting Services report. DMX, although powerful, does lack some basic query functionality that might be desirable for showing data mining results.

SQL Server 2005 : Extending Your Database System with Data Mining - Data Mining Applied (part 1)

SSAS data mining is no less programmable than OLAP, and although SSAS data mining can sometimes be more straightforward than OLAP development, for the most part the two are comparable in complexity.

# Oracle Coherence 3.5 : Achieving Performance, Scalability, and Availability Objectives (part 2)

You can scale an application up by buying a bigger server or by adding more CPUs, memory, and/or storage to the existing one. The problem with scaling up is that finding the right balance of resources is extremely difficult. You might add more CPUs only to find out that you have turned memory into a bottleneck.

# Oracle Coherence 3.5 : Achieving Performance, Scalability, and Availability Objectives (part 1)

When building a distributed system, another important factor we need to consider is network latency. The duration of every operation is the sum of the time it takes to perform the operation, and the time it takes for the request to reach the application and for the response to reach the client.

MySQL Server Monitoring (part 3) - Server Logs, Third-Party Tools & The MySQL Benchmark Suite

If you are a seasoned Linux or Unix administrator, you are familiar with the concepts and importance of logging. The MySQL server was born of this same environment. Consequently, MySQL has several logs that contain vital information about errors, events, and data changes.

MySQL Server Monitoring (part 2) - MySQL Administrator

The MySQL Administrator is a jack of all trades. It provides facilities for viewing and changing system variables, managing configuration files, examining the server logs, monitoring status variables, and even viewing graphical representations of performance for some of the more important features.

MySQL Server Monitoring (part 1) - SQL Commands

All of the SQL monitoring commands are a variant of the SHOW command, which displays internal information about the system and its subsystems.

Using MySQL Enterprise (part 3) - Query Analyzer

The Query Analyzer runs over the user-defined port 6446 (by default) and can introduce some performance delay. Thus, you should enable it only when you are searching for problems.

Using MySQL Enterprise (part 2) - Monitoring

If you create a reporting mechanism that monitors a custom application, you can create an advisor for it and add alerts to the Enterprise Dashboard. The specific details of how to add new advisors and alerts are covered in the MySQL Enterprise Monitor manual on the Enterprise subscription portal.

Using MySQL Enterprise (part 1) - Installation & Fixing Monitoring Agent Problems

There are several user accounts involved in the installation of MySQL Enterprise. Besides your Enterprise subscription account, you will also be using a MEM administrator, an agent access account to your MEM server, and an agent access account for the monitoring agent running on each MySQL server.

Getting Started with MySQL Enterprise & MySQL Enterprise Components

One of the most powerful tools available to an attacker building an XSS exploit is being able to generate requests to the target website from the victim’s browser and being able to read the responses.

Transact-SQL in SQL Server 2008 : Table-Valued Parameters

In previous versions of SQL Server, it was not possible to share the contents of table variables between stored procedures. SQL Server 2008 changes that with the introduction of table-valued parameters, which allow you to pass table variables to stored procedures as input parameters.

Transact-SQL in SQL Server 2008 : New date and time Data Types and Functions

If an existing CONVERT style includes the time part, and the conversion is from datetimeoffset to a string, the time zone offset (except for style 127) is included.

Defensive Database Programming with SQL Server : When Snapshot Isolation Breaks Code

Queries that may previously have been blocked, in lock-waiting state, under traditional isolation levels, can complete when running under the snapshot isolation levels. This feature is highly useful in many situations but, unfortunately, it may in some cases break existing code, such as triggers.

Protecting SQL Server Data : SCHEMA ARCHITECTURE STRATEGIES - Using Views

Views are objects within SQL Server that provide a layer of abstraction between the end users and the underlying schema. Rather than directly access the base table, the users query a "virtualized table" that holds only the data that is specific to their needs.

Creating and Managing Views in SQL Server 2008 : Indexed Views

You establish indexed views by creating a unique clustered index on the view itself, independent of the member tables that it references. The creation of this unique index transforms a view from an object that is virtual in nature to one that has physical storage associated with it.

Transact-SQL in SQL Server 2008 : Row Constructors

SQL Server 2008 provides a new method to insert data to SQL Server tables, referred to as row constructors. Row constructors are a feature that can be used to simplify data insertion, allowing multiple rows of data to be specified in a single DML statement.

Transact-SQL in SQL Server 2008 : GROUP BY Clause Enhancements

The old-style CUBE and ROLLUP syntax is still supported for backward-compatibility purposes but is being deprecated. You should convert any existing queries using the pre-2008 WITH CUBE or WITH ROLLUP syntax to the new syntax to ensure future compatibility.

Creating and Managing Views in SQL Server 2008 : Partitioned Views

Partitioned views are used to access data that has been horizontally split, or partitioned, across multiple tables. These tables can be in the same or different databases—or even spread across multiple servers.

Creating and Managing Views in SQL Server 2008 : Managing Views, Data Modifications and Views

After creating your view, you can manage the view via T-SQL or the View Designer. The T-SQL commands for managing views are the ALTER VIEW and DROP VIEW statements.

Creating and Managing Views in SQL Server 2008 : Creating Views

One of the most amazing features of the View Designer is the capability to render a SQL statement into its graphical form. You can copy T-SQL into the SQL pane, and the View Designer reverse-engineers the tables into the Diagram pane, giving you a graphical display of the query

Creating and Managing Views in SQL Server 2008 : Definition of Views & Using Views

Views are a logical way of viewing data in the underlying physical tables. They are tied to a SELECT statement that retrieves data from one or more tables or views in the same database or a different database.

Transact-SQL in SQL Server 2008 : Insert over DML

The OUTPUT clause allows you to return data from a modification statement (INSERT, UPDATE, MERGE, or DELETE) as a result set or into a table variable or an output table.

Transact-SQL in SQL Server 2008 : MERGE Statement

With the MERGE statement, you can synchronize two tables by inserting, updating, or deleting rows in one table based on differences found in the other table, all in just a single statement, minimizing the number of times that rows in the source and target tables need to be processed

SQL Server 2008 : Transact-SQL Programming - The TABLESAMPLE Clause

You can use TABLESAMPLE to quickly return a sample from a large table when the sample does not have to be a truly random sample at the level of individual rows.

SQL Server 2008 : Transact-SQL Programming - TRY...CATCH Logic for Error Handling

SQL Server 2005 also introduced the TRY...CATCH construct, which you can use within T-SQL code to provide a more graceful mechanism for exception handling than was available in previous versions of SQL Server.

SQL Server 2008 : Transact-SQL Programming - The APPLY Operator

The APPLY relational operator allows you to invoke a table-valued function once per each row of an outer table expression. You specify APPLY in the FROM clause of a query, similarly to the way you use the JOIN operator. APPLY can take two forms: CROSS APPLY and OUTER APPLY.

SQL Server 2008 : Transact-SQL Programming - PIVOT and UNPIVOT

SQL Server 2005 added the PIVOT clause to T-SQL. A typical analytical use of the PIVOT command is to convert temporal data into categorized data to make the data easier to view and analyze.

SQL Server 2008 : Transact-SQL Programming - Ranking Functions

SQL Server 2005 introduced four new ranking functions: ROW_NUMBER, RANK, DENSE_RANK, and NTILE. These functions allow you to analyze data and provide ranking values to result rows of a query.

SQL Server 2008 : Transact-SQL Programming - Common Table Expressions

Nonrecursive CTEs are ANSI SQL-99 compliant expressions that provide T-SQL coding flexibility. However, for each nonrecursive CTE, there is usually another T-SQL construct that can be used to achieve the same results (for example, derived tables)

SQL Server 2008 : Transact-SQL Programming - The OUTPUT Clause

In SQL Server 2005, the INSERT, UPDATE, and DELETE statements were enhanced to support an OUTPUT clause to be able to identify the actual rows affected by the DML statement.

SQL Server 2008 : Transact-SQL Programming - TOP Enhancements

The TOP clause allows you to specify the number or percentage of rows to be returned by a SELECT statement. SQL Server 2005 introduced the capability for the TOP clause to also be used in INSERT, UPDATE, and DELETE statements.

SQL Server 2008 : Transact-SQL Programming - The max Specifier

In SQL Server 2000, the most data that could be stored in a varchar, nvarchar, or varbinary column was 8,000 bytes. If you needed to store a larger value in a single column, you had to use the large object (LOB) data types: text, ntext, or image.

SQL Server 2008 : T-SQL Tips and Tricks (part 3) - Generating T-SQL Statements with T-SQL & De-Duping Data with Ranking Functions

The system catalogs in SQL Server 2008 contain a wealth of information you can use to save a lot of time and effort when generating SQL statements that need to be run repeatedly on a large number of database objects or when trying to build a column list for a query.

SQL Server 2008 : T-SQL Tips and Tricks (part 2) - Using CONTEXT_INFO & Working with Outer Joins

An outer join is used to return all the rows from the specified outer table (specified with LEFT OUTER, RIGHT OUTER, or FULL OUTER), even if the other table has no match. Rows returned from the outer table that have no corresponding match in the inner table display the value NULL for any columns retrieved from the inner table.

SQL Server 2008 : T-SQL Tips and Tricks (part 1) - Date Calculations & Sorting Results with the GROUPING Function

As you may know, working with the datetime data type in SQL Server can be a bit of a challenge. You probably already know how to use the datepart() function to extract specific components of a date (for example, year, month, day).

SQL Server 2008 : General T-SQL Performance Recommendations

How you write T-SQL queries can often have an effect on the performance of those queries. The following sections provide some general guidelines to keep in mind to help ensure that you are getting optimal performance from your queries.

SQL Server 2008 : General T-SQL Coding Recommendations (part 2) - Avoid SQL Injection Attacks When Using Dynamic SQL & Comment Your T-SQL Code

SQL injection is usually the result of faulty application design—usually an unvalidated entry field in the application user interface.

SQL Server 2008 : General T-SQL Coding Recommendations (part 1) - Provide Explicit Column Lists & Qualify Object Names with a Schema Name

In SQL Server 2005, the behavior of schemas was changed from earlier versions of SQL Server. SQL Server 2005 introduced definable schemas, which means schemas are no longer limited to database usernames only.

SQL Server 2008 : Advanced Stored Procedure Programming and Optimization - Using Extended Stored Procedures

Extended stored procedures are invoked and managed similarly to regular stored procedures. You can grant and revoke permissions on extended stored procedures as you do for normal stored procedures