Database Administrator

PL/SQL Developer Practical Skills 1. PL/SQL Developer remember the Login Password When PL/SQL Developer is used, PL/SQL Developer needs to remember the username and password for logging on to Oracle for ease of work; Setting Method: PL/SQL Developer

MySQL Error Log) Like most relational databases, log files are an important part of MySQL databases. MySQL has several different log files, such as error log files, binary logs, common logs, and slow query logs. These logs help us to define what

Analysis and Solution of ORA-12516 errors A ORA-12516 error occurs when you use swingbench to perform a stress test on the Oracle database. This error is generally because the number of oracle sessions exceeds the limit, generally because multiple

BitMap indexes are more efficient than B-Tree indexes. 1. Experiment description: Operating System: rhel 5.4x86 Database: Oracle 11g R2 Ii. Procedure: Create a t_btree table and create a B-Tree index. The index key is status: SQL> create table

Implement MapReduce in Oracle Database When programmers develop parallel programs, the Map-Reduce mode is becoming popular. These map-reduce programs usually process large amounts of data in parallel. This article demonstrates how to implement the

Binary installation MySQL-5.7.4 Database MySQL 5.7.4 significantly improves query performance, which is doubled from MySQL 5.6. On the test platform, it can reach 512000 read-only QPS per second, while MySQL 5.6 can only reach 250000 QPS. This

MySQL master replication + Keepalived to create a highly available MySQL Cluster In response to the company's needs, we have created a safer mysql cluster to implement mysql failover. After several days of research, we can finally share the results.

Use GoldenGate to synchronize data from MySQL to Oracle in real time Use GoldenGate to synchronize data from MySQL to Oracle in real time Step 1: Configure mysqlModify the configuration file my. ini# For goldengateLog-bin = "C:/mysql/logbin.

ORA-12519 error process error After the system runs normally for one month, the following error occurs on the first day of the launch. After a long time, you have no idea. Later find the database listening exception, found that ORA-12519 rejection

Use flashback to view historical Oracle table time data Use flashback to view historical Oracle table time data 1. View historical table time data Select * from tab_test as of timestamp to_timestamp ('2014 10:00:00 ', 'yyyymmdd hh24: mi: ss '); 2

Problems caused by inconsistent Oracle field type design and actual business During the design of the Oracle table, developers always disagree with the field type. The following example shows how to design the field as number and the result is

Create a tablespace in Oracle and test it with the user The Oracle tablespace is described as follows: Temporary tablespace: used for grouping operations when sorting large data volumes. Normally, these operations are completed in the memory, but

Practice: mysql version upgrades   /*************************************** * ************ Upgrade mysql to 5.6.21 ********************* * ******************************/backup is required before the upgrade! ---- 1. view the data directory location

MySQL auto_increment_increment, auto_increment_offset usage, autoincrement In MySQL, you can specify the auto_increment attribute of the column when creating the table for the ID auto-increment column. It is equivalent to the identity attribute in

VB. NET and SQL databases, and VB. NETsql Databases Data contains rich information. Data is a resource. The connection operations to SQL databases are slightly different for different languages due to their respective syntax features. However, the

The user specified as a definer ('root' @ '%') does not exist, specifieddefinerZookeeper is generally because the root user has no access permission to the global host. Therefore, you only need to add an access permission to the root user. Solution:

Is the DML statement an error because the control file cannot be expanded or is there another reason ?, Dml also has Today, I have handled a very interesting fault problem. The reason is as follows:   The customer's incoming call consultation

Oracle 11gR2 cannot export empty tables with exp solution, 11gr2exp Oracle 11gR2 cannot export empty tables with exp Solution There is a new feature in 11gR2. When the table has no data, no segment is allocated to save space. Oracle cannot export

Trigger and trigger instance Although I have been familiar with triggers, I am not very thorough. Sometimes I still don't quite understand them. Now I want to add this blank space. The trigger content is basically as follows: Note: When a trigger

Objects in ADO. NET: Connection, Command, DataReader, DataAdapter, DataSet, and able, It may be because I didn't make a good summary at the beginning. NET. objects in. NET have been vague. Today, I reviewed them again. I checked the information,