Database Administrator

MongoDB replica set building and adding/Removing Machines 1. replica set You must set the replica set name for each replica set. This parameter is specified when MongoDB is started. 2. Setup steps 2.1 start Start MongoDB first Set to replica set

MongoDB learning notes 01 MongoDB installation and use, mongodb learning notes Recently, due to work needs, I began to contact mongodb, so I began to study mongodb. The first step of the study was naturally from installation and use. there will

Clob is saved as a local xml file. After modification, it is uploaded. clobxml I wrote a small program with my friends over the past two days. The functions are as follows: First, save the database clob as a local xml file, modify the xml file, and

Should varchar or datetime be used for the field type of date stored in the database ?, Varchardatetime Background: Some time ago, I saw an article "how to show your (lover) name in the lower right corner of my computer" in Baidu experience. I have

SQL server statement exercises, SQL server statements Related tables: create table DEPT(deptno int not null primary key,dname varchar(14)  null,loc varchar(13) null)create table EMP(empno int not null primary key,ename varchar(10) null,job varchar(9)

In the Oracle 11g environment, you can use utl_smtp to create a storage process for sending mails, 11gutl_smtp If there are too many email storage processes on the internet, I will not forward them. Let's make a simple example; Create or replace

The relationship between tts and character sets -- requires that the source and target database character sets must be the same, and the national character sets must be the same ., Tts Character SetThe relationship between tts and character sets --

Oracle OS authentication and password file authentication method, oracleosOS Authentication 1. In the SQLNET. ORA (located in the $ ORACLE_HOME/NETWORK/ADMIN directory) file, use vi to edit and comment out the line # SQLNET. AUTHENTICATION_SERVICES =

ORA-00942: Table or view does not have a low-level error example, ora-00942 example ORA-00942: a low-level error does not exist in a table or view   Run the query statement and report a ORA-00942 Error   After checking, the user who does not

Why is it possible to log on to the oracle database as sysdba and enter your username and password ?, Sysdbaoracle This is actually a problem with oracle database authentication.In the sqlnet. ora fileSQLNET. AUTHENTICATION_SERVICES =

Terminating the instance due to error 481 causes the ASM to fail to start. terminatingasm1. symptom description When a RAC database is accidentally shut DOWN, the first node starts normally, but the second node cannot start ASM and CRS resources.2.

Interview Questions, java interview questions 1. Use case when for subquery SELECT u.id user_id,u.username user_username,g.id group_id, CASE g.flag WHEN '0' THEN g.groupcode ELSE (SELECT t.fullname FROM tab_0009 t WHERE t.id = g.id)

Oracle calculates the total (very useful), oracle1-12 for 1-12 months of a yearCase studies Query the total number of real population from January 2015 to 12 months and the number of real population from January 2014 to 12 months in previous years.

MySQL-11-stored procedure, mysql Stored Procedure Stored Procedure The commonly used operating database language SQL statements must be compiled and then executed before execution. The Stored Procedure (Stored Procedure) is a set of SQL statements

Connect time out occurs in mongodb on the java linked server. mongodbconnect Exception Information December 22 5:27:58 PM com. mongodb. DBTCPConnector initDirectConnectionWarning Exception executing isMaster command on/192.168.1.249: 10003Java. io.

[Oracle] Chapter 1 create authorization, Chapter 1 Authorization of oracle Chapter 1 create authorization in ORACLE Run the following command to view control files, data files, and log files: Control File: Desc v $ controlfile; Data File: desc v $

Migrate the oracle database from the 32-bit platform to the 64-bit, oracle32-bit The disk of the customer's 32-bit oracle database system is damaged. Fortunately, the oracle database is intact. The customer requested that the database be migrated to

SQL tracking and tkprof usage, SQL tracking tkprof usageBrief Introduction In oracle databases, awr is a report on the overall load and running status of the database system. However, when the system load is normal, and the client executes some

Monitor the remaining time of SQL Execution, and monitor the remaining time of SQL -- Monitor the remaining time of SQL Execution. Do you know how long the running SQL takes? Do you know that the running SQL statement has completed about a few

C3p0 displays An attempt by a client to checkout a Connection has timed out, java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)at