Database Administrator

When we define a very complex cursor, this cursor takes a long time to execute. During the execution of this cursor, other users modify the data of the table referenced by this cursor, does cursor get the data before or after modification? The

1. view the table created by the user (Table Name and comment) -- View the table name Select*FromUser_tab_commentsWhereTable_nameLike 'Tb _ %'; If: 2. view the table name, column name, and field type information. SelectCol.

I have been very interested in the principles and practices of distributed systems for a long time, and I have been very curious about Mongodb. I have finally had time to experiment with it! I set up a Replica Sets + Sharding test cluster

I have previously studied how to build a mongodb environment (see). Considering that the mongodb cluster environment will be used in the future and the multi-bit 32-bit OS environment, I have constructed a mongodb cluster environment. For details

Based on the "Mongodb cluster configuration (sharding with replica set)" cluster (SEE), try to dynamically Add a shard replica set when the Mongodb cluster is running. (1) Start the replica set Node Run the following three batch files to start three

1. Modify records directly in the databaseMysql> use mysqlMysql> update user set password = password ("new_password") where user = "user_name ";Mysql> flush privileges;In fact, this method is to update a database record. Unlike normal update

I. in Oracle databases, we usually use the following methods to copy or migrate records between tables in different databases: 1. The records in Table A are exported to insert statements separated by semicolons and then inserted into Table B. 2.

Follow the steps of configuring dbstart for Oracle 10g on the Internet to enable auto-startup. the startup is successful and the record is as follows: 1. Modify the dbstart script:$ Vi $ ORACLE_HOME/bin/dbstart# ORACLE_HOME_LISTNER

Today, I downloaded Oracle Linux 6.1 and installed it on a virtual machine. I am going to use it to install ORACLE 11G R2 (11.2.0.3). I suddenly found that yum cannot be used. I found it online, find the SETUP document on the

1. The LONG data type stores variable-length strings with a maximum length limit of 2 GB. 2. For text that exceeds a certain length, the LONG type can only be used for storage. Many objects in the data dictionary are defined as LONG. 3. The LONG

1. Switch to the database user on the console: su-OracleIi. Input: lsnrctl start; start the listener;3. Start the database;4. operate databases, such as creating users, granting permissions, and creating tables;5. Shut down the database;6. Disable

Symptom description:The following error message is returned when the ASM storage management cannot join the disk:SQL> alter diskgroup disk add disk '/dev/rdsk/c2t500601603022E66Ad13s6 ';Alter diskgroup disk add disk

Oracle Regular Expression Functions                                       2. REGEXP_LIKE (x, pattern [, match_option]) is used to find the Regular Expression pattern in x. This function also provides an optional parameter match_option string to

The Spool buffer pool technology in Oracle can be used to export Oracle Data to text files. 1. Enter the buffer start command in Oracle PL/SQL and specify the output file name: Spool d:/output.txt   2, Set heading off -- remove the field name Set

1. Create a stored procedureProc code Create or replace procedure changesalary (p_employeeid number, p_newsalary number) is Begin Update employees set salary = p_newsalary Where employee_id = p_employeeid; If SQL % notfound then

First, change the lazy property to false. Type 2: Add OpenSessionInViewFilter org. springframework. orm. hibernate3.support. OpenSessionInViewFilter flushMode AUTO OpenSessionInViewFilter /* The above two methods have some problems. Third,

When Grid Control 10.2.0.3 is installed on RHEL5.4 and configured in OMS, an error occurs:Configuration assistant "OMS Configuration" failed-----------------------------------------------------------------------------The

First, the previous image shows the truth. Note: 1. Read a data table with more than rows, and then write data to the local table. 2. Tables of the big field type are not included. Note: 1. I recently performed data import/export operations.

Oracle 10046 is an Oracle internal event. The most common method is to set SQL _trace (alter Session set SQL _trace = true) at the session level, that is, to enable the 10046 debugging event of level 1. After a 10046 event is set, Oracle generates a

Recently, I participated in a company project and planned to quickly respond to large-scale queries on the online platform. The estimated total data volume is about 2-3 billion records, the database concurrency is about 1500 per second, and the