Database Administrator

New Features of Oracle 12C-Extended Data Types New Feature of Oracle 12C-extended data types. In 12c, compared with earlier versions, data types such as VARCHAR2, NAVARCHAR2, and RAW are extended from 4 K and 2 K bytes to 32 K bytes. As long as

Reading the return values of Oracle functions using Python Create a function in Oracle to return an index table. When we thought that the text could also transmit information, we suddenly came to the inspiration and set the return value to the text

Use udev for ASM in Oracle Linux6.7 1. RequirementsOracle Linux6.7 uses udev as asm/Dev/sdb /dev/asm-diskb/Dev/sdc /dev/asm-diskc/Dev/sdd /dev/asm-diskd/Dev/sde /dev/asm-diske/Dev/sdf /dev/asm-diskf 2. FaultIn Oracle Linux 6.7 under vmware vshpere5.1

Three methods of MySQL backup The main function of MySQL backup is to quickly, efficiently and securely solve problems in the case of hardware faults, software faults, natural disasters, hacker attacks, and human error, so as to avoid unnecessary

Deploy Redis3 in CentOS7 CentOS7 Redis3 Study Notes 1 Official Redis Website:Http://www.redis.io/ 2 Redis:Http://download.redis.io/releases/redis-3.0.7.tar.gzHere we download the redis-3.0.7.tar.gz 3 Redis introduction:Redis is an open source (BSD

Oracle archiving logs Archive Log is a non-active backup of redo logs. archive logs can be used to keep all redo history records. When the database is in ARCHIVELOG mode and the log is switched, the background process ARCH will save the redo log

Are Fields in MongoDB documents sorted in order? In this article, we will briefly discuss the sequence of fields in Mongodb. The document in Mongodb is a Json string consisting of Key: Value pairs. It is reasonable to say that the order of fields

Install MySQL 5.7.10 on Mac OS X I tried to install MySQL on the Mac over the past two days. I didn't expect the simple action that I thought would have wasted so much time. I wrote it here. It's a mark, to save some detours for later students. At

MySQL master-slave replication interrupt error code = 1217 error resolved MySQL master-slave replication is interrupted and the Error "error on master: message (format) = 'could not delete or update a parent row: a foreign key constraint fails

Simple use of MySQL event -- View the create information of the event Show create event event_test; -- View the event status in a schema SELECT event_schema, event_name, status from information_schema.events WHERE event_schema = 'xxxx'   -- Check

A simple MySQL performance query script A simple MySQL performance query script is as follows: #!/bin/shmysqladmin -P3306 -uroot -p'password' -r -i 1 ext |\awk -F"|" \"BEGIN{ count=0; }"\'{ if($2 ~ /Variable_name/ && ((++count)%20 == 1)){\ print

Oracle imports the local dmp backup file into the local Oracle database. Oracle imports the local dmp backup file into the local Oracle database. Import syntax Imp usename/password @ SID full = y file = d: \ data \ xxxx. dmp ignore = y Import

Subscription and release of apsaradb for Redis Document directory 1. Why subscription distribution? 2. Subscription publishing in Redis 3. Redis producer consumer 4. Subscription and release in Redis 5. Java Jedis's pitfalls Why subscription

Oracle knowledge sorting: More than Oracle Common heap table limitations:Table update with log overhead table deletion with flaws table record too large slow retrieval index back table read overhead large ordered insertion difficult to orderly read

MongoDB $ type OperatorDescription The $ type operator is based on the BSON type to retrieve matching data types in the set and return results. The following table lists the types that MongoDB can use: Type Number Remarks

MyBatis Study Notes Speaking of mybatis, let's first talk about ibatis. mybatis3.X is a later version of ibatis2.X, which has many more powerful functions than ibatis. 1. Comparison between mybatis and ibatis 1.1 In terms of relationship ing,

Basic Oracle Database Operations Basic Oracle database operations. All usernames and passwords created by Oracle are bkjia Create user bkjia identified by bkjia Assign permissions to the user name Grant resource, dba, connect to bkjia; Change

MongoDB query documentSyntax The syntax format of MongoDB data query is as follows: >db.COLLECTION_NAME.find() The find () method displays all documents in an unstructured manner. If you want to read data in a readable manner, you can use the pretty

Use Redis to store the follow relationship Redis provides a wide range of data types. Compared with relational databases or simple Key-Value storage (such as Memcached), Redis data models are more similar to actual data models. For example, in the

Oralce creates a userPrerequisites Note that you must first Log On As SYSDBA. You can select the logon role on some development tools.If it is a command lineAs sysdbaCreate user process To create an Oracle database, you can use the SQL developer