Database Administrator

Oracle ascii Functions 1 Introduction The Oracle ascii function is used to return the numeric code of a single character. Second syntax ASCII (single_character) parameter description: indicates that only one character can be entered. If multiple

Oracle update and order Today, I encountered a problem about converting SQL statements into Oracle statements, which is described as follows: Select * from emp order by deptno; Select * from dept; SQL Server: Update dept a set dname =

Oracle troubleshooting ORA-01089 After sending the shutdown immediate command to the test database today, observe the log and find the following content:Tue May 12 09:52:45 2015SHUTDOWN: Active processes prevent shutdown operation Shutdown is

How to Delete more than 10 million normal heap table data from Oracle Database Delete Requirement: delete an Oracle database to delete 10 million historical records from a common heap table. Impact of direct deletion: 1. The deletion may fail due to

Examples of global and local indexes and global indexes-- Create a tableCreate table lm_t1 (id number, name varchar2 (10), sex varchar2 (10 ))Partition by range (id)(Partition p1 values less than (10 ),Partition p2 values less than (20 ),Partition

SQL Syntax: "add", "delete", "modify", "query", and SQL syntax /* 4. Check 1. common query syntax: select from [where ] [order by [asc or desc] * // * 1 ). query all data rows and columns: select * from a description: Query all rows in Table a

Database interview questions-competition data query and question Data Query This interview is quite special. I gave a test paper and asked to give a verbal answer. To be honest, I really like it. The last question is the database question. The table

The index creation rules for mysql optimization and the index Optimization for mysql The data structure commonly used for indexing is B + tree.. The structure is as follows: For example, it is a B + tree. For the definition of B + tree, see B +

Java jdbc simple encapsulation and java jdbc simple Encapsulation After learning jdbc for a while, I felt like I could try to write a simple encapsulation, so I wrote a little bit about some of the reference materials. After all, I didn't learn it

The role and case of master-slave replication in Beckham _ mysqlMysql master-slave ReplicationBrief:I. mysql user authorization II. mysql bin-log III. mysql master-slave Replication   I. mysql user authorization 1. Commands 2. Role: Permission

Treap basic learning and treap basic learning Working in the company now, the weekend boss asked us to study in the company. because there were no projects recently, we used the data structures we did not have before to learn. Then we saw a Treap

MongoDB master-slave and replset test, mongodbreplset1. masterslavemaster configuration file: dbpath = ../data_test/db/masterLogpath = ../data_test/master. logPort = 8642Logappend = trueOplogSize = 2048StorageEngine = wiredTigerNojournal = trueSlave

Mysql creates and deletes users and authorizations (for linux testing), and mysqllinux Note: My runtime environment is SUSE Linux + mysql5.6 1. Create a user:Command: create user 'username' @ 'host' identified by 'Password ';Description:

Code error: 1327 Undeclared variable: p_film_count, undeclared 1. Error description 1 queries executed, 0 success, 1 errors, 0 warnings query: SELECT FOUND_ROWS () INTO p_film_count error code: 1327 Undeclared variable: p_film_count execution

MySQL displays "error 1067: Unexpected Process Termination", and mysql1067 1. Error description 2. Error cause Today, I am exploring how to use commands to view MySQL logs. I have checked a lot of information, mostly by modifying the

Union, except T, intersect, and unionintersect in SQL 1. union: Use union: combine two result tables to eliminate duplicate records. Use union all: combine two result tables (repeated values are not duplicated ). 2. Failed t: Use distinct T:

Obtains the maximum number of rows in a column in all groups. How to obtain the maximum row of a column in all groups? The following is an example: There are several employees in the company. Each employee has its own id, group_id (department) and

Linux c programming to access the database, linux to access data The source code is as follows: # Include # include # include int main () {/* defines the mysql variable */MYSQL * coon; // The handle MYSQL_RES * res used for database connection; /

How to query duplicate data and delete duplicate records in Oracle For example, there is a personnel table (table name: peosons) drop table PERSONS; create table PERSONS (PNAME VARCHAR2 (50), CARDID VARCHAR2 (18), ADDRESS VARCHAR2 (100 )); insert

Beckham _ mysql partition theory learning, Beckham _ mysql theory learningMysql PartitionBrief:I. Why mysql partition II? mysql partition type III. mysql partition technology comparison   I. Why mysql partitioning? 1. When business data increases,