Database Administrator

Oracle input error count modification, user unlock, password expiration By default, Oracle databases lock users after 10 failed attempts; 1. view the FAILED_LOGIN_ATTEMPTS Value Select * from dba_profiles; 2. Change it to 30 alter profile default

Case study of SQLyog client unable to connect to MySQL Server-- View the Client ip Address [root @ mysql ~] # W 22:20:43 up, 1 user, load average: 0.00, 0.01, 0.05 user tty from login @ idle jcpu pcpu WHATroot pts/1 192.168.1.7 22:23:15 3.00 s 0.07

ORA-27090 fault case and ora-27090 fault case The recent alert Log encountered an error message for the ORA-27090 with the error prompt Unable to reserve kernel resources for asynchronous disk I/O. According to this prompt, It is a kernel parameter

Relationship Pattern Design Theory and Pattern Design Theory Normalization: A low-level paradigm can be transformed into a relational model of several advanced paradigms through Mode Decomposition, that is, normalization. Paradigm: Currently,

Oracle how to ensure the ACID principle of transactions -- oracle Core Technology Reading Note 2, acid -- oracle There are four general principles in the transaction that all databases must comply with, referred to as the ACID principle. The

Oracle Performance Analysis 8: Creating indexes and oracle performance indexes When creating an index, we often want to estimate the index size to evaluate the impact on the existing engineering environment. We also hope that the index creation

Use Case Analysis of database Optimization Using Virtual Index and virtual Case AnalysisWhen we optimize the production database, we mainly optimize SQL statements, including equivalent statement rewriting. However, a large part of the optimization

Execute each line in the job, and execute the jobZookeeper Execute each line in the job Sometimes, we need to execute a job or a conversion multiple times, and each input parameter is different. If you are migrating data and need to import old data

Install two mysql database steps in Windows: mysql databaseBecause the database versions of the new and old projects are too different, the encoding format is different, and the engine is also different, so we have to install two databases.Two mysql

ORA-00600: internal error code, arguments: [keltnfy-idmlnit], [46], [1], [], [], [], [], [], [], error When DBCA reaches 3%, an error is returned. An error is reported because/etc/hosts does not match/etc/sysconfig/network. [Root @ ocm2 ~] #

In the oracle database, the connection test statements in the application are correctly used.Correct use of connection detection statements in applications in oracle databases This article is the original article, reprint please indicate the source:

Sqlite Study Notes 4: Create and Delete tables and sqlite Study Notes If you have done so much, isn't it just to get a few tables for data? Let's take a look at how to create a new table. 1. Create a table The basic syntax is as follows: CREATE

Solution-SQL Server Remote connection failure, SQL Server When the charging system of the IDC is released remotely, you must ensure that the database can be remotely connected. However, an error is usually reported during connection:   To solve

ADO. NET-data reader, DataReader --- ShinePans, Depending on different data providers, DataReader can be divided into four categories: SqlDataReader, OleDbDataReader, OlbeDataReader and OracleDataReader A clever analogy: if the database is a

Use awrextr. SQL to export awr raw data and awrextr. SQL to export awr1. Differences between original AWR data and AWR reports  AWR raw data: The oracle Database mmon Process regularly dumps statistics from memory to disk and stores them in several

Storage Structure and transactions, storage structure transactions The restructured data center charging system is implemented by three layers. When I started simple addition, deletion, and modification, I was able to say that I had to learn

High Availability of MySQL-keepalivd + mutual master and slave, mysqlkeepalivdObjective: to configure a keepalived Hot Standby architecture and master-slave ReplicationPlanning:Master1 zlm177 192.168.17.177Master2 zlm188 192.168.17.188Vip 192.168.17.

Summary of oracle constraints (not null/unique/primary key/foreign key/check), oracleunique Constraints: restrict the column attributes and fields of the created table. Such as: not null/unique/primary key/foreign key/check Scope:① Column-level

What is a tablespace? 1. view the tablespace and datafile corresponding to a userSelect t1.username, t2.tablespace _ name, t2.file _ name, t1.temporary _ tablespace, t3.file _ nameFrom dba_users t1Left joinDba_data_files t2On t1.default _ tablespace

SQL for xml query sample, xmlsample Sample 1: declare @x xml select @x=' EveryMonday 2000-01-01T19:30:00 EveryThursday 2000-01-01T19:30:00 EverySunday 2000-01-01T19:30:00 'SELECT