Oracle

Database Common keywords:CREATE TABLE --- Create a tableCreate a table with table name (column name type of column, column name Type of column ... )CREATE TABLE Z_course (ID number, Cour_code VARCHAR2 (), Cour_name VARCHAR2 (), p_cour_code VARCHAR2

public class Test {private static final SimpleDateFormat FORMAT = new SimpleDateFormat ("Yyyy-mm-dd HH:mm:dd");public static void Main (string[] args) throws SQLException {Oracle.sql.TIMESTAMP temp = new Oracle.sql.TIMESTAMP ();SYSTEM.OUT.PRINTLN

First, disable constraintsALTER TABLE table_name DISABLE NOVALIDATE constraint constraint_nameSecond, bulk import dataBe sure to check the violation of the constraint before opening the constraint record1. Execute the script Utlexpt1.sql from Oracle

substr intercept FieldSUBSTR (string, intercept start position, intercept length)SUBSTR (STR,N,M)Second, the three parameters can be omitted,The second parameter is a negative number, which means to intercept m from the nth bit of the

Considering that using R to connect directly to Oracle is highly convenient for reading data, try using roracle to connect.1. Download Rtool2. Set environment variables (be careful not to overwrite)Set Oci_lib32 = c \instantclient_11_2Set path = c:

Error detail Description: Error:ora-01034:oracle not availableora-27101:shared memory realm does not exist process id:0 session id:0 serial number: 0Solution:1. Running[Email protected] admin]$ sqlplus ' sys/[email protected]: 1521/ORCL as Sysdba '2.

Application Scenarios:According to keyword query and this keyword similar information, some of the keyword to exclude such as: "Limited Liability Company", "Co., Ltd." and so on, need to create an exclusion thesaurus table;First step: Thesaurus

Select File#,name from V$datafile;Select File#,name from V$tempfile;SELECT NAME from v$controlfile;--control fileSelect Group#,sequence#,status from v$log;--redo log fileShow parameter spfile;--database initialization fileSelect

Oracle Self-Growth ID:Reference blog: Automatic incrementing of the Oracle Database creation table ID fieldMyBatis statementsReference blog: Reviews ibatis+oracle three ways to bulk insert. Refer to the third typeReference Blog: Two ways to BULK

----------------------------multitable Insert------------------------------------------------Insert All----------------------------------------------------SELECT * from EMP;CREATE TABLE Sal_history (Empid Number (4), HireDate date, SAL number (7,2));

SELECT * from EMP; EMPNO Ename JOB MGR HireDate SAL COMM DEPTNO 1 7369 SMITH Clerk 7902 1 July-December-80 800 20

The Variance function variance (x),The specific methods are:The variance s,a is the average of X1,X2...XN,then S = [(x1-a) ^2+ (x2-a) ^2+ (x3-a) ^2+ ... (xn-a) ^2]/nStandard deviation function StdDev (x),The specific algorithm is:The variance is

Common scenario: When backing up an Oracle database from the server and restoring the Oracle database on the local machine, you often encounter inconsistent database character encoding, and can use the following command to change the local Oracle

Sql%notfound is a Boolean value. Interacts with the most recent SQL statement (Update,insert,delete,select), which returns True when the most recent SQL statement does not involve any rows. Otherwise, false is returned. Such statements are useful in

4.oracle database Start-up processWindows operating systemStart monitoring: Lsnrctl start;Start DB instance: oradim-startup-sid Instance NameLinux SystemsStart monitoring: Lsnrctl start;Launch DB instance: Sqlplus Sys/change_on_install as

TRUNC (Number,num_digits)Number requires a truncated rounding.The num_digits is used to specify the number of rounding precision. The default value for Num_digits is 0. If the num_digits is a positive number, the num_digits bit after the decimal

Today in the use of PLSQL query data query a SQL statement, after the execution of what results are not, at first thought that the SQL statement is wrong, because the previous will know to check the table can not have no data, and then went to the

One, the Oracle General function VNL (A, A, a, b) for any type, if the value of a is NOT NULL returns the value of a, otherwise returns the value ofConditional judgment can be used in OracleCase FieldWhen condition 1 then expression 1When condition 2

Why is the data generated by Oracle garbled?the installation of the database and the client encoding code inconsistencies will produce garbled, To fix this problem, change the client code to1. select * FROM table;If this is the problem there are

--View all users under the database:Select from Dba_users;--View the user roles for the current connected databaseSELECT * from User_role_privs;--Create UserCREATE User by test;--Assigning authorizationGrant to -- assign permissions to allow