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  Mysql common basic operation commands

  1 connection Mysql format: mysql-h host address-u user name-p user password 1, connect to the MYSQL on this machine. First open the DOS window, then enter the directory mysql\ bin, and then type the command mysql-u root-p

  2022-06-01 13:31:47 Views: 205
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  Problems caused by 1-5 major transactions

  When the system crashes, it is found that there are no committed transactions, and some operations will be rolled back (1) in the first window begin; select from t where id < 7;-> 1 35 (2) in the second window begin; in

  2022-06-01 13:31:17 Views: 254
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  MySQL creates a database

  MySQL to create databases using mysqladmin to create databases using ordinary users, you may need specific permissions to create or delete MySQL databases. So we use the root user to log in, and the root user has the highest privileges, so you can use the

  2022-06-01 13:31:11 Views: 214
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  Capture problematic SQL- slow log

  Slow query records: many slow query logs may be generated. It takes time to view the slow query logs manually. You can use the tool mysqldumpslow: provided by mysql. (only count is added, the number of times the sql statement is executed. That is, this appears many times in the slow query log

  2022-06-01 13:31:03 Views: 263
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  Oracle max_seq_calc

  DECLARETYPE seq_st_tt IS TABLE OF INT;seq_st seq_st_tt: = seq_st_tt (20, tmpsum, 10, 5, 5, 3, 5, 4, 4, 2, 7, 40)

  2022-06-01 13:30:50 Views: 223
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  The replacement advantage of Vertica in Communication Industry

  one。 Background Analysis the traditional relational database occupies a solid dominant position in the enterprise market for a long time, and many people do not realize that there are other types of databases besides the traditional relational database. Traditional relational databases are very good at transactional operations such as update operations. But dealing with a large amount of data

  2022-06-01 13:30:50 Views: 299
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  Take the same field and the maximum record of another field in SQL

  Sql takes the record with the highest value of the B field of the repeated record in the A field select max (id) id,name from table group by name-if there are other fields in the table to find out, then the select * from table

  2022-06-01 13:30:49 Views: 221
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  Oracle11gR2 uses RMAN duplicate to replicate the database-- active database duplicate

  11gR2's RMAN duplicate feels much more advanced than 10g, which needs to be replicated on the basis of rman backup, using RMAN duplicate to create a database with identical data but different DBID. And 11.

  2022-06-01 13:30:49 Views: 227
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  Comparison between Windows Azure Pack and VMware VRA (VI) Azure Pack MSSQL PaaS function Test

  Platform as a Service (platform as a service, PaaS) is a cloud computing service that provides computing platforms and solution stacks as a service. In the typical level of cloud computing, the platform as a service layer is between software as a service and infrastructure as a service. The platform is

  2022-06-01 13:30:36 Views: 230
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  PostgreSQL's MVCC vs InnoDB's MVCC.

  One of the most important functions of any database is extensibility. If you do not delete each other, there is as little lock competition as possible to achieve this goal. Because read, write, update, and delete are the most important and frequent operations in the database, they are not performed concurrently.

  2022-06-01 13:30:23 Views: 285
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  Oracle11g and PL/SQL11.0 login issu

  ORA-12560:TNS: protocol adapter error resolution: 1) the listening service is not up. The windows platform operates as follows: start-programs-management tools-services, open the services panel, and start oraclehome92TNSli

  2022-06-01 13:30:23 Views: 288
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  Oracle collection operation

  Collection keywords: 1, UNION: Union, all contents are queried, displayed once repeatedly, sorting in ascending order by default; 2, UNIONALL: Union, all contents are displayed, including duplicates, display content is not sorted; 3, INTERSECT: intersection, only show more

  2022-06-01 13:30:05 Views: 202
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  Holer implements external network access to local SQLServer database

  The external network accesses the internal network SQLServer database. The SQLServer database is installed on the internal network host, which can only be accessed in the local area network. How can the local SQLServer database be accessed from the public network? This article describes the specific steps to implement using holer. 1. Preparatory work

  2022-06-01 13:30:05 Views: 225
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  Hadoop+hbase+zookeeper fully distributed installation (2)

  As soon as the installation is ready, we can continue to install hbase after we have successfully installed hadoop. According to the corresponding table in the previous article, we choose to download the appropriate version of hbase. The version selected for this case is hbase-0.94.10.tar.gz. Zookeepe

  2022-06-01 13:29:57 Views: 276
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  SQL SERVER modifies the table name

  Exec sp_rename 'table1',' table2'

  2022-06-01 13:29:56 Views: 276
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  Mongodb3.,4.4 installation based on centos7 system

  Download and install mongodbwget https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-rhel70-3.4.4.tgztar zxvf mongo

  2022-06-01 13:29:56 Views: 209
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  Batch upload of Mybatis

  Mybatis provides a method of batch upload. In fact, you only need to configure sql statements in xml. Let's directly look at the implementation: insert into rfid_raw_eri (tid, bzhh, bzxh)

  2022-06-01 13:29:56 Views: 292
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  016-Optimization

  Some optimization suggestions: 1. The execution performance of SELECT statements can be checked through explain statements. 2. Database object stored procedures are faster than individual execution statements. 3. Reduce the frequency of select *. 4. Indexes can speed up data queries, but not often.

  2022-06-01 13:29:56 Views: 227
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  MySQL test

  MySQL database system MySQL features: multi-process, multi-user, high performance, high reliability and ease of use MySQL AB-- > SUN-- > OracleMySQL-- > MariaDB relational database RDBMS: business: Oracl

  2022-06-01 13:29:55 Views: 206
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  Index Optimization Series 15-- Combinatorial query and in-related Optimization

  Drop table t purge;create table t as select * from dba_objects;update t set object_id=rownum; create

  2022-06-01 13:29:55 Views: 296