Database Administrator

I. Software Environment 1. windows nt4.0 + oracle 8.0.4 2. oracle installation path: c: \ orant Ii. Meaning   Iii. Usage 1. Compare the size Select decode (sign (variable 1-variable 2),-1, variable 1, variable 2) from dual; -- smaller value

MySQL provides standard SQL mode matching and an extended regular expression mode matching format based on Unix utilities such as vi, grep, and sed. Standard SQL mode matching SQL pattern matching allows you to use "_" to match any single character,

In the process of diagnosing database system performance, SQL statements with low tracking efficiency are always involved. Oracle Database 10 Gb contains a new utility trcsess, it allows you to selectively extract trace data from a large number of

# Valid Oracle identifiers 1. It cannot be a reserved keyword. 2. It must contain 1 to 30 characters. The database name cannot exceed 8 characters. 3. It must start with a letter in the database Character Set 4. Only letters in the database

The following operations are successful in Oracle9i and 10g. Step 1: create a directory object for storing XML files SQL>createorreplacedirectoryexp_diras'/opt';/ -- Note that the directory must have the write permission of the

If you are familiar with Oracle databases, I think you will not be familiar with ThomasKyte. The asktom.oracle.com website hosted by Tomas has been well-known in the Oracle field for decades and is far from Lucky. Recently in the library by the

BKJIA exclusive release] Oracle 11g R2 has been released. This update has many new features. Integration reduces costs and eliminates unused redundancy. Let's take a look at the attractive new features added in Oracle 11g R2. Server cost reduced by 5

This article is intended for database administrators who want to learn about Oracle. It is hoped that this article will give you a deeper understanding of the time, numbers, and character formats in Oracle. BKJIA database also recommends the Oracle

1. Check whether you should use a MySQL cluster. Reduce the pressure on the data center nodes and process large data volumes. MySQL is distributed and one or more applications correspond to one MySQL database. Share data with the common data of

When a Cassandra cluster needs to be invested, initialization data is usually used, for example, all the blog data on a blog website, all the webpage information on a data analysis website, and all the product information on an e-commerce website.

BKJIA database channel has previously reported the world of Infobright in the column database. The overall architecture of Infobright is shown below: As shown in, Infobright adopts the same architecture as MySQL and is divided into two layers. The

The following articles mainly introduce the specific content of MySQL limit query optimization. We all know that MySQL database optimization is very important. Limit is the most commonly used and optimized. MySQL limit greatly facilitates paging.

The execution plan is simply the result calculated by the query optimizer, which indicates the most efficient way to execute the submitted query. The execution plan tells you how the query is executed, so it is the basic means for DBA to diagnose

To fulfill Oracle's commitment to adding SQL-optimized query intelligence, Oracle9i enhances the full-index SQL Execution Plan to support function-based indexes based on functions ). In Oracle8, the SQL optimizer adds intelligence to determine

Multi-Table operations Multiple tables may exist in a database, which are associated with each other. We will continue to use the previous example. The preceding table contains basic information about an employee, such as name, gender, date of

Note: Data can be migrated from SQL Server 2000 to Microsoft SQL Server 200064 bits ). You can attach a 32-bit database to a 64-bit database by using the sp_attach_db system stored procedure or sp_attach_single_file_db system stored procedure, you

Whether in a small free database space or a large e-commerce website, it is necessary to reasonably design the table structure and make full use of the space. This requires us to fully understand the Common Data Types of database systems. Next I

Recently, Sybase, an enterprise architecture and mobile software provider, has released its fourth-generation advanced programming language, 4GL, Fast Application Development (RAD) tool Sybase PowerBuilder 11. With its advantages in rapid

Summary ASE has become a high-performance leader in OLTP (on-line transaction processing, online transaction processing) systems. However, users now need not only high transaction processing performance, but also Analysis of the transaction data of

Database optimization is a complex task, because it requires a good understanding of system optimization. Although the optimization effect is good if you do not know much about the system or application system, you need to know more about it if you