Oracle

1. Create a normal user tableCreate Table Demo ( intnotnull, varchar(ten), varchar (default'123' ,primary Key (ID))2. Create a sequence sequenceCreate sequence Seq_demo by 1-Self-increment 1 with 1--Start value 1 Nomaxvalue--No

implementing a row merge using Wmsys.wm_concatIn Oracle, multiple rows of data from one field are converted to a comma-styled line. Can be achieved using function Wmsys.wm_concat.This one in the previous articleOracle Built-in function

Oracle Paging query statements make one of our most commonly used statements, as described below, for the use of Oracle paging query statements, and if you are interested in this aspect, you may wish to take a look.Oracle Paging query statements can

1. Download instantclient-basic-win32-11.2.0.1.0(Oracle official Website:http://www.oracle.com/technetwork/topics/winsoft-085727.html, 2:http://download.csdn.net/ detail/czw2010/5732241) 2. Unzip the instantclient-basic-win32-11.2.0.1.0 and place

It is easy to understand that a company is likened to a server, and the database is a department in the company.1.SID: A database can have multiple instances (such as RAC), and the SID is used to identify the name of each instance within the

Because a backup script for Oracle needs to be written recently, Oracle's data backup is not backed up directly using binary tools like MySQL, and data backup on Oracle needs to be configured so that normal data backup scripts can be configured. So

Linux System launches Oracle command Su-oracleSqlplus/nologConn/as SYSDBAStartupExitLsnrctl startExit Linux System shutdown Oracle command Su-oracleSqlplus/nologConn/as SYSDBAShutdown immediateExitLsnrctl stopExit

ORACLE:1, check the name of the primary key:SELECT * FROM User_constraintsWHERE table_name = ' AAA 'and Constraint_type = ' P ';Chape corresponding columns:SELECT * FROM User_cons_columnsWHERE table_name = ' AAA 'and constraint_name = ' pk_aaa ';

Management of Oracle Tables--Adding dataInserting data into a table using the INSERT statementInsert Data basic syntax:INSERT into table[(column [, Column ...])] VALUES (value [, value ...]);insert into table name [(column name [, column Name 2 ...])

Basic syntax for building a table:CREATE TABLE table_name (Field1 datatype,Field1 datatype,Field1 datatype,...)NOTE : table_name table name; field specifies the column name (field name); datatype specifies the column type (field data type)Note: When

The time partition can be partitioned according to the day of the month and the day, generally according to the daily or monthly partition is sufficient, here according to the day partitionDemo is as followsCREATE TABLE Apdemo (OID number generated

Recently participated in a number of interviews, summed up the competition in the Oracle development post most frequently asked what questions:1, delete and truncate difference? 1) Truncate is a DDL statement. Delete is a DML statement;2) Truncate

Recently participated in several interviews. Summarize the most frequently asked questions about the competition for Oracle development positions:1, delete and truncate difference? 1) Truncate is a DDL statement, and delete is a DML statement;2)

Recently in the business travel ticket platform, encountered such a problem:There is a tt_ticket table that is used to store ticket information. Inside there is a field called schedule, which represents the itinerary, the storage format is:

Oracle Querying for duplicate dataSELECT * FROM table where condition and weight field not in(Select Judgment weight field from table where Condition group By field has count (*) > 1)Delete duplicate data according to ROWID, keep aDelete from table

# Python connects Oracle data# # Introduction------------------------------Python connects Oracle database and can use Cx_oracle module-Install using the following command```python-m pip Install cx_oracle--pre```# # Connect Oracle Code---------------

Since the project team is doing things with the DBA, it's not long before the DBA is gone, and almost the "chores" of the database are followed.Small white one, only Jingxiao micro operation. Often see the high water level and low water situation,

Select substr (object_name,1,30), substr (os_user_name,1,20) from v$locked_object,user_objectswhere v$locked_object.object_id = user_objects.object_idSelect B.owner,b.object_name,a.session_id,a.locked_modeFrom V$locked_object a,dba_objects bwhere

--Add, modify, and delete constraints--1. Add Constraint ALTER TABLE tableAdd[constraint constraint]Constraint_type (column1[, Column2,...])[constraint_parameters];Alter TableBooks Modify Title not NULL;--add a non-null constraint--2. Modifying

The merge into statement is a new syntax for merging update and INSERT statements in oracle9i.Through the merge statement, the other table is queried based on the join criteria of a single table or multi-table union query, and an update on the join