Database Administrator

The SQL statement is as follows: Select * from LOAN_BACK_LIBRARY where LIBRARY_ID = 1 or LIB_ID = 1 and STATUS = 3 The conditions for my desired results are:1. LIBRARY_ID = 1 or LIB_ID = 1 2. STATUS = 3 But this is not the case. STATUS is displayed!

I. What is a grouping function? The grouping function acts on a group of data and returns a value for a group of data. Ii. Grouping function types Avg, count, max, min, stddev (standard variance), sum. Function Name Function Description

-- Recode Data TypeDeclareV_deptinfo scott. dept % rowtype;Type dept_record is RECORD (V1 scott. dept. deptno % type,V2 scott. dept. dname % type,V3 scott. dept % rowtype-- The ROWTYPE can be declared.);V_deptrecord dept_record;Begin-- The following

In hibernate, the object class is queried using hql statements, and the returned result of the list method is a List. The objects encapsulated in the List are divided into the following three situations:1. When you query all fields, such as "from

1. If the default port 1521 is used and the instance is automatically registered to the listener, you do not need to set local_listener. The listener. ora file can be configured as normal. 2. If a non-default port 1521 is used to enable the instance

Use of the Oracle 10g wmsys. wm_concat row and column conversion function:First, let's take a look at this magic function wm_concat (column name). This function can separate the column values with "," and display them as a row. Next, let's take an

Today, I will explain the new features of Oracle 11g Database-virtual Columns Introduction In the old Oracle version, when we need expressions or some calculation formulas, we will create a database view. If we need to use indexes on this view, we

Here, we will talk about the processing of all nouns in Oracle10g. The following string contains all nouns in one of the words. BeginDbms_output.put_line ('1' | 'nimeng's dog ');End; Execution error: ORA-01756: the string in the brackets does not

Oracle LISTENER does not listen to Oracle instances. solution: LISTENER =(DESCRIPTION_LIST =(DESCRIPTION =(ADDRESS = (PROTOCOL = IPC) (KEY = EXTPROC1521 )))(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP) (HOST = qihezhiye-PC.connectify) (PORT = 1521

Install the Oracle client software:Root Account execution:# Groupadd oinstall# Groupadd dba# Useradd-g oinstall-G dba oracle# Passwd oracleCreate an oracle basic directory:# Mkdir-p/u01/app/oracle# Chown-R oracle: oinstall/u01# Chmod-R 775/u01/U01

In the standard of SQL, the transaction isolation level is divided into the following four types:1. Read uncommitted)2. Read committed)3. Repeatable read)4. Serializable)However, PostgreSQL versions earlier than 9.1 only implement two of them: Read

Oracle em grid control 10.2.0.2 is installed on a windows Server, and an existing database is used as the database. The oracle emgrid agent software is installed on various linux servers for monitoring the oracle database and rac system. The agent

I. Index type:PostgreSQL provides a variety of index types: B-Tree, Hash, GiST, and GIN. Because they use different algorithms, each index type has a suitable Query type, saving time and resources, the create index Command creates a B-Tree INDEX.1.

1. When LGWR is idle, it will check whether any data is written from redo buffer to redelog every 3 seconds. If yes, a background process will automatically write the data into it. 2. When a process needs to allocate space from the redo buffer, the

1.Function 1) Create a function Create or replace function get_tax (x number) Return number Begin Declare y number; Begin Y:=X-2000; If x= 0 then Return 0; End if; Returns y * 5/100; End; End

In the database synchronization process, both the Database loading efficiency and the atomicity of each transaction in the database must be ensured, that is, the execution of Multiple SQL statements in a transaction must be successful for the above

Download mysql-5.1.60-linux-x86_64-glibc23.tar.gz to/home/a/soft/ Shell> sudo groupadd mysqlShell> sudo useradd-r-g mysqlShell> cd/home/a/soft/Shell> tar zxvf mysql-5.1.60-linux-x86_64-glibc23.tar.gzShell> cd/usr/local/Shell> sudo

TCMalloc (Thread-Caching Malloc) is an open-source tool developed by google --"Google-perftools. Compared with the standard glibc library's malloc, TCMalloc has much higher efficiency and speed in memory allocation, which can greatly improve the

You can use the scott password triger, an existing Oracle account, to log in and use the existing table to perform the test. Create or replace procedure lpmtest2 As Para1 varchar2 (10); Cursor youbiao is select ename from test where sal>1300;

The most typical application of Database Synchronization is Remote Disaster Tolerance and the query statistics of the primary database. This is generally a one-to-one application. However, the demand for multi-dimensional synchronization sometimes