Tutorials,Articles,Algorithms,Tips,Examples about Database

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SQL Server 2012 : Encryption Support (part 4) - Transparent Data Encryption - Enabling TDE, Backing Up the Certificate

Once you’ve created a certificate-protected DEK for the database, you can start the encryption process. Encryption occurs in the background and does not interfere with applications that are concurrently accessing the database.

SQL Server 2012 : Encryption Support (part 3) - Transparent Data Encryption - Creating Keys and Certificates for TDE

To start using TDE, you need to create a certificate, and to create a TDE certificate, you need to create a DMK. Although DMKs and certificates, in general, can be created in any database, they must be created in the master database when you intend to use them for TDE.

SQL Server 2012 : Encryption Support (part 2) - Encrypting Data at Rest

Social Security or other government-issue identification numbers, credit card numbers, salary information, driver’s license numbers, passwords—the list of sensitive information just keeps going.

SQL Server 2012 : Encryption Support (part 1) - Encrypting Data on the Move

All connection login requests made to SQL Server are encrypted if the client is using the SQL Server Native Access Client application programming interfaces (APIs).

SQL Server 2012 : Authentication and Authorization (part 2) - User-Schema Separation,Execution Context

Imagine that an employee in an organization who has created many tables and stored procedures leaves the company. As a database administrator, your task is to reassign ownership of all the objects that this former employee created and owned.

SQL Server 2012 : Authentication and Authorization (part 1) - How Clients Establish a Connection, Password Policies

If a TCP client wants to make a connection to SQL Server, it must first know which port to connect to. Prior to SQL Server 2005, there was always a thread waiting on User Datagram Protocol (UDP) port 1434 whose purpose was to return details on all of the running instances of SQL Server, as well as the port numbers of those instances.

SQL Server 2012 : SQL Server Security Overview

If you are already familiar with the concepts of users and roles and SQL Server logins. But for those who aren’t, we’ll provide a quick explanation. The concepts of users and roles exist both in the Microsoft Windows world and in SQL Server.

SQL Server 2012 : Working with Transactions - Transactions in SQL CLR (CLR Integration)

We noted that in PSPE, a distributed transaction might not be distributed. Thus, the boundaries of what is distributed and what is not are already blurry. Well in SQL CLR, they are not only blurry, they are downright indistinct.

SQL Server 2012 : Distributed Transactions (part 4) - Using a Resource Manager in a Successful Transaction

By doing so, you would note that your VolatileRM now participates in the same transaction that a database query has enlisted itself in. This is something that BEGIN DISTRIBUTED TRANSACTION cannot do because by its very nature it talks to database queries, which cannot perform nondatabase operations.

SQL Server 2012 : Distributed Transactions (part 3) - Distributed Transactions in the .NET Framework - Writing Your Own Resource Manager

It is only reasonable to expect that because databases are the most critical part of the architecture (at least to database developers and administrators!), they have had fantastic transactional support for a long time.

SQL Server 2012 : Distributed Transactions (part 2) - Distributed Transactions in the .NET Framework

The concept of distributed transactions was not introduced with the .NET Framework. Prior to the .NET Framework, you could enlist in distributed transactions using third-party transactions coordinators such as COMTI or solutions such as COM+ or Microsoft Transaction Server (MTS) to enlist in distributed transactions.

SQL Server 2012 : Distributed Transactions (part 1) - Distributed Transaction Terminology, Rules and Methods of Enlistment

You will frequently encounter the terms resource manager, transaction manager, transaction coordinator, and two-phase commit when discussing distributed transactions. Let’s look at those terms more closely.

Protecting SQL Server Data : TRANSPARENT DATA ENCRYPTION (part 6) - Reversing the Implementation of TDE

You may find yourself in a situation where TDE has been implemented, you have validated that it works, are ready for users to begin using the newly-encrypted database and then, lo-and-behold, a request to reverse TDE comes your way.

Protecting SQL Server Data : TRANSPARENT DATA ENCRYPTION (part 5) - Verifying TDE - Verification through Backup and Recovery

Another method of verifying the success of a TDE implementation is to perform a backup of the database, after TDE has been enabled, as shown in Listing 9. When doing so, make sure not to overwrite the backup file that was created prior to implementing TDE.

Protecting SQL Server Data : TRANSPARENT DATA ENCRYPTION (part 4) - Verifying TDE - Using Dm_Database_Encryption_Keys

Dynamic management views (DMV) are built-in views that provide metadata regarding the settings, health and properties of SQL Server instances and databases.

Protecting SQL Server Data : TRANSPARENT DATA ENCRYPTION (part 3) - Implementing TDE - The User Database

Having created the database master key and the MasterCert certificate in the Master database, we are ready to create the database encryption key for the HomeLending database which we will use to perform the cryptographic functions for the physical files of our database.

Protecting SQL Server Data : TRANSPARENT DATA ENCRYPTION (part 2) - Implementing TDE - Backup before Proceeding , The Master Database

At this point in the process you should perform a backup of the certificate with its private key, using the BACKUPCERTIFICATE command shown in Listing 5. In the event that the HomeLending database needs to be restored, this certificate and its private key will be required.

Protecting SQL Server Data : TRANSPARENT DATA ENCRYPTION (part 1) - How TDE Works, Considerations when Implementing TDE

Transparent Data Encryption (TDE) was introduced in SQL Server 2008, as a feature of the Enterprise Edition of that product. The Developer Edition of SQL Server 2008 also offers TDE, but its license limits its use to development and testing only.

SQL Server 2012 : Isolation Levels (part 2) - Repeatable Read Isolation Level,Snapshot Isolation Level, Isolation Levels in ADO.NET

There is a slight mismatch between the isolation levels defined in ADO.NET (which calls SQL Server from your .NET application), compared with the isolation levels in SQL Server itself. This is because ADO.NET was not written exclusively for SQL Server, and is a generic data access technology that supports Oracle and other databases as well.

SQL Server 2012 : Isolation Levels (part 1) - Read Uncommitted Isolation Level, Read Committed Isolation Level

SQL Server 2012 : Local Transaction Support in SQL Server (part 2) - Implicit Transaction Mode, Batch-Scoped Transaction Mode

Since SQL Server 2005, multiple active result sets (MARS) are supported on the same connection. Note that we said multiple active results, not parallel execution of commands. The command execution is still interleaved with strict rules that govern which statements can overstep which other statements.

SQL Server 2012 : Local Transaction Support in SQL Server (part 1) - Explicit Transaction Mode

The autocommit transaction mode enables you to run single queries in a transactional manner, but frequently you’ll want a batch of queries to operate within a single transaction.

SQL Server 2012 : What Is a Transaction?

A transaction is a single operation or set of operations that succeed or fail together as a whole, thereby ensuring consistency of data should unforeseen circumstances arise.

MySQL : The Binary Log - Binary Log Options and Variables

Several options control such properties as the name of the binlog files and the index file. Most of these options can be manipulated as server variables as well.

MySQL : The Binary Log - The mysqlbinlog Utility (part 2) - Interpreting Events

Sometimes, the standard information printed by mysqlbinlog is not sufficient for spotting a problem, so it is necessary to go into the details of the event and investigate its content. To handle such situations, you can pass the --hexdump option to tell mysqlbinlog to write the actual bytes of the events.

MySQL : The Binary Log - The mysqlbinlog Utility (part 1) - Basic Usage

One of the more useful tools available to an administrator is the client program mysqlbinlog. This is a small program that can investigate the contents of binlog files as well as relay logfiles . In addition to reading binlog files locally, mysqlbinlog can also fetch binlog files remotely from other servers.

SQL Server 2012 : Exploring SQL CLR - Examining and Managing CLR Types in a Database

Once deployed, your SQL CLR stored procedures, functions, triggers, aggregates, and UDTs, and their dependencies, might become difficult to keep track of in your head.

SQL Server 2012 : Exploring SQL CLR - Security

When you deploy an assembly from Visual Studio, its security level is set to Safe by default. To change it, double-click the Properties node in the Solution Explorer, click the SQLCLR tab in the resulting property sheet designer and then select SAFE, EXTERNAL_ACCESS, or UNSAFE from the Permission Level combo box.

SQL Server 2012 : Exploring SQL CLR - SQL CLR Types

The last SQL CLR feature for us to explore is user-defined types (UDTs). This feature is perhaps the most interesting facet of SQL CLR integration, yet also the most controversial.

SQL Server 2012 : Exploring SQL CLR - CLR Aggregates

T-SQL has a number of built-in aggregates, such as SUM, AVG, and MAX, but that set of built-in functions is not always sufficient. Luckily, the SQL CLR features in SQL Server 2012 allow us to implement user-defined aggregates in .NET code and use them from T-SQL. User-defined aggregates can be implemented only in SQL CLR code; they have no T-SQL equivalent.

SQL Server 2012 : Exploring SQL CLR - CLR Triggers

T-SQL triggers are really just stored procedures that are called by SQL Server at specific times and that can query values in the DELETED and INSERTEDSQL CLR triggers are similar to SQL CLR stored procedures, and they can be created for all data manipulation language (DML) actions that modify data. pseudo-tables .

My SQL : Replication for High Availability - Procedures (part 8) - Circular Replication

After reading about dual masters, you might wonder if it is possible to set up a multimaster with more than two masters replicating to each other. Since each slave can only have a single master, it is only possible to get this by setting up replication in a circular fashion.

My SQL : Replication for High Availability - Procedures (part 7) - Slave Promotion - Slave promotion in Python

You have now seen two techniques for promoting a slave: a traditional technique that suffers from a loss of transactions on some slaves, and a more complex technique that recovers all available transactions.

My SQL : Replication for High Availability - Procedures (part 6) - Slave Promotion - A revised method for promoting a slave

The traditional approach to promoting a slave is inadequate in most cases because slaves usually lag behind the master. Figure 9 illustrates the typical situation when the master disappears unexpectedly.

My SQL : Replication for High Availability - Procedures (part 5) - Semisynchronous Replication - Configuring semisynchronous replication

To use semisynchronous replication, both the master and the slave need to support it, so both the master and the slave have to be running MySQL version 5.5 or later and have semisynchronous replication enabled.

My SQL : Replication for High Availability - Procedures (part 4) - Dual Masters - Replicated disks using DRBD , Bidirectional replication

When using dual masters in an active-passive setup, there are no significant differences compared to the hot standby solution outlined earlier. However, in contrast to the other dual-masters solutions outlined earlier, it is possible to have an active-active setup .

My SQL : Replication for High Availability - Procedures (part 3) - Dual Masters - Shared disks

A straightforward dual masters approach is shown in Figure 4, where a pair of masters is connected using a shared disk architecture such as a SAN (storage area network).

My SQL : Replication for High Availability - Procedures (part 2) - Hot Standby

The easiest of the topologies for duplicating servers is the hot standby topology. This topology is shown in Figure 2 and consists of the master and a dedicated server called a hot standby that duplicates the main master. The hot standby server is connected to the master as a slave, and it reads and applies all changes.

My SQL : Replication for High Availability - Procedures (part 1) - The mysql.com Outage

Unlike many other IT teams I have met over the years, these guys are comfortable handling the complex array of computers that MySQL has accumulated over the years—everything from high-end Windows machines to very old SGI Irix and HP-UX machines—keeping it all together with whatever means they have at their disposal.

My SQL : Replication for High Availability - Redundancy, Planning

To understand where redundancy might be needed, you have to identify every potential point of failure in the deployment. Even though it sounds easy—not to mention a tad tedious and boring—it requires some imagination to ensure that you really have found them all.