Database Administrator

DETERMINISTIC in Oracle I have been confused when I saw DETERMINISTIC for many times. I did an experiment today. We assume that Oracle is a DETERMINISTIC function, which is called only once in SQL. If DETERMINISTIC is not used, the values are

Oracle 11g adds not null fields faster than 10g-new feature, oracle11g Adding a not null field before 11g is very slow, and it is very fast after 11g. We will first perform a test and then explore the principle. SQL> select * from v $ version;BANNER

Python for sqlserver and pythonsqlserver# Coding = gbkImport sysImport pymssql# Try database connectionTry:Conn = pymssql. connect (host = "192.168.1.43", user = "sa", password = "sa01! ", Database =" master ")Failed t pymssql. OperationalError, msg:

Data room charging system-view application and data room Charging System View I learned about the view in database learning and self-examination a year ago. At that time, I only learned the theory. This time I personally practiced it in the

MySqL + MySQLWorkbench + PyCharm and mysqlworkbench are installed on mac. Today, MySqL + MySQLWorkbench + PyCharm is installed on mac. Installing these things is not familiar with windows. The installation program on Mac is really not very suitable,

The problem of attaching a higher version to a lower version of the database is that My computer room charging system was knocked out on my laptop. After I knocked it out, I copied the database and put it on the desktop. I was going to use the

Recompile the invalid database component and compile the invalid database component. You can validate different components in the database by running the script $ ORACLE_HOME/rdbms/admin/catpatch. SQL via SQL * Plus:     Spool catpatch.

Mysql string replacement, mysql stringI have the following requirement: there is a field in the data, for example, "0-300". Now we need to replace the data with "0 ~ 300 ".The SQL statement is as follows: UPDATE tj_item_result SET reference_range =

How does the select_related and prefetch_related functions of Django optimize QuerySet queries? (3) djangoqueryset This is the last article in this series, mainly the best practices of select_related () and prefetch_related. The first section

Sorts a field in a database table by deduplication. 1. Problem background In a database, t_tab_ AB has two fields, a and B, as shown below: Before query: After query: A B 1 2 1 2 1 3 2 3 1 4 3 4 1 5 2 3 2 4 2 5 3 4 3 5 2. Solution Groups and sorts

Concatenate multiple mysql fields and mysql Fields The following two functions can be used to concatenate the query result line Fields of Mysql: 1. concat Function mysql> select concat('1','2','3') from test ;+---------------------+| concat('1','2',

Mysql performance debugging tool profile, mysqlprofile I have been looking for mysql tools similar to Oracle 10046. I can see the time consumption of SQL Execution. I finally found a profile on the Internet. I think it is good to use it. Mysql>

Oracle Performance Analysis 1: Enabling SQL tracking and obtaining trace files, oracletrace When there is an issue with Oracle query efficiency, we often need to understand the problem so that we can provide a solution to the problem. Oracle

Sqlite learning notes 8: Using sqlite to create a table in C language, sqlite learning notes We have already discussed how to open and close the database, and how to execute SQL statements to create a table. Functions to be

The description of the status in lsnrctl, lsnrctlstatus LSNRCTL> statusConnecting to (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP) (HOST = lixora) (PORT = 1521 )))STATUS of the LISTENER------------------------Alias LISTENERVersion TNSLSNR for Linux:

Add a joint primary key in oracle and an oracle joint primary key Alter table tablename add constraint unionkeyname primary key (column1, column2 ); In the preceding statement: Tablename is the table for which the Union constraint is to be added.

JDBC connection to Oracle database and jdbcoracle Database I remember when I was in my sophomore year, we took a java course. At that time, the teacher said JDBC, and I didn't know how to learn it well. Until now, I didn't know what JDBC was, I know

Preparation of the vb report template of the data room Charging System (I ). The data room charging system has the report function, which is a bit unfamiliar to us. Isn't it an accounting task? How is the data room Charging System Integrated? In

The correct installation of oracle11g plsql under the win7-64bit, oracle11gplsql I have installed the Oracle 11g Database Service on my PC. I cannot connect to the database through PL/SQL because PLSQL does not have a 64-bit version, an error is

Create a new user and modify the maximum number of connections at oracle11g, and create at oracle11g Create user test identified by root; grant create session, resource to root; alter user test account unlock; grant create view to test; grant any