Oracle

Type Meaning Storage description Note CHAR Fixed-length strings Maximum length 2000bytes 　 VARCHAR2 Variable-length strings , Maximum length 4000bytes Maximum length of index

Environment preparationNode One: CentOS 6.8 x86-64CPU:4C Memory: 8g swap:8gBusiness ip:192.168.50.20 Private Network ip:10.98.50.20Node two: CentOS 6.8 x86-64CPU:4C Memory: 8g swap:8gBusiness ip:192.168.60.21 Private Network ip:10.98.50.21Database

A. function1. c2b function: Clob to BLOBCreate or Replace functionC2B (binchClobdefaultEmpty_clob ())returnblob isres blob; Blen Number:=Dbms_lob.getlength (b); DestOffset1 Number:= 1; SrcOffset1 Number:= 1; AMOUNTCinteger:=dbms_lob.lobmaxsize;

Oracle Common database field typesCommon database field types are as follows: Field type Chinese description restrictions other description CHAR fixed length string max length bytes VARCHAR2 variable length string maximum length 4000 bytes can do

Connect Linux Server Operations Oracle database   because the project is online, the site's database server is not allowed to connect directly with Oracle's client Plsqldev.exe, and can only be manipulated by commands from the Linux server. The

Oracle Delete User prompt cannot delete the currently connected user two solutions are as follows: 1, first lock the user, then query the process number, and finally delete the corresponding process, in the deletion of the corresponding users

Oracle (Oracle) officially released VirtualBox 5.0.22, the latest maintenance version of the open source and cross-platform virtualization software has been open to all support platforms, introducing many new features and features to improve the

Once a period of time to write SQL statements, always inexplicably reported ora-01722.For this error, especially for a complex SQL statement, is very depressed, because many times do not know.Through each encounter summary, in fact, is not so

Oracle (Oracle) officially released VirtualBox 5.0.22, the latest maintenance version of the open source and cross-platform virtualization software has been open to all support platforms, introducing many new features and features to improve the

Because there is no automatic growth in Oracle, you need to do the writing trigger, and so on to set up:Look for someone else to write, there are two ways to set the primary key, one is self-growing primary key, and the other is to generate a unique

One, compressed table spaceThe compressed tablespace is implemented by compressing objects within the table space. The compression of data is reflected in the data block, which is simply to reduce I/O and improve performance performance by clearing

non-routine recovery with Oracle Dul tool to recover data from drop-deleted Oracle data tables without backupDul to recover a drop object, you need to provide two information1. Table space to which the deleted table belongs (not required)2. Deleted

/* Formatted on 5/24/2012 4:15:58 PM (QP5 v5.149.1003.31008) */SELECT Deptno,ename,--st_name | | "| | Last_Name Employee_Name,HireDate,SalSTDDEV (SAL) over (PARTITION by Deptno ORDER by HireDate) as "STDDEV", standard deviationStddev_samp (SAL) over

1.%type DECLARE dname DEPT. Dname%-- dynamically defines the type of variable that changes with the type of Dname field in the Dept Table . BEGIN SELECTinto fromWHERE DEPTNO=; Dbms_output. Put_Line (dname); END

SELECT * from EMP;--1. Identify 30 of employees in the departmentSELECT * from emp where deptno = 30;--2. List the names, changes, and department numbers of all clerks (clerk)SELECT * from emp where job = Upper (' clerk ');--3. Identify employees

There are three ways to start Oracle Services: 1 from Control Panel 2 using MS-DOS command 3 via Oracle Administration Assistant for WindowsNT-Start Oracle Service via Control Panel 1) Select Start > Control Panel management Tools--〉 Service 2)

One, multi-table queryA multi-table query is a query that queries data from multiple tables that are associated with a syntax similar to a single-table query. In general, tables with multiple table queries are linked together, and if not, the query

To achieve the current time, week, month, quarter, half year, years of conversion, where special attention is to the processing of the week, the IW way of handling logic, if this week has greater than or equal to 4 days, this week belongs to a few

1. Use explain plan for to get the execution planPlan for sql>; Select * from Table (Dbms_xplan.display ());The results are as follows:--------------------------------------------------------------------------------------------------------------- -

1. Definition and function of the parameter fileThe Oracle database configures the database through a series of parameters. These parameters are expressed in the form of key-value pairs, such as:Maxlogfiles=50Background_dump_dest=c:dumpWhere the