Oracle

[Oracle] string parsing generates associated data because the project function sometimes needs to be provided by other departments in Excel... in other documents, some data is inserted into the database tables without interruption, so a simple

Oracle architecture basics 1. physical structures (consisting of control files, data files, redo log files, parameter files, archive files, and password files) data in a database is stored in physical files on disks, when used, it is transferred to

The statements you should know in ORACLE are frequently used. We should remember that, however, the human brain is not a computer, and we may regret them when we forget to use them, so we will record them one by one, there will also be traces for

Oracle stored procedure and serialized write demo 1. create an Oracle stored procedure, set a parameter n, run the stored procedure, and pass the parameter n. After the execution, the output is five times hello world. Note: The for loop is used in

Sqlplus learning notes (2) set the length of the line to 200 characters and then line feed [SQL] set linesize 200 note: Sqlplus command does not need to write ";" Semicolon SQL statement must end with a semicolon, the Sqlplus command can be used as

Greenplum manages indexes. Considering the characteristics of OLAP systems, you should use indexes carefully and conservatively. Avoid using indexes on frequently updated columns; use B-tree indexes on highly selective columns; and use Bitmap

Before oracle arhivelog mode Backup recovery, let's take a look at the role of archive: 1. when a media fault occurs, it can be restored (whether online or offline, to the specified time point, and to the end of the log file (until cancel. back up

Connect to the same database instance with the same SID. The two instances are on different servers, such as my tnsnames file # tnsnames. ora Network Configuration File: D: \ oracle \ product \ 10.2.0 \ db_1 \ NETWORK \ ADMIN \ tnsnames. ora #

Database Learning (3) -- database creation and deletion (2) -- SQL language Overview http://www.bkjia.com/database/201305/207487.html In the subsequent operations section, we recommend that you install MySQL for your convenience. The installation of

Oracle optimization query Skills 1. connection sequence in WHERE clause: ORACLE uses the bottom-up sequence to parse the WHERE clause. According to this principle, the connection between tables must be written before other WHERE conditions, the

The web OS commander External table web External table is read-only and can not be written as a conventional external table, while the OS commander web External table is a deformation body. For details, refer to several examples. Gtlions = # create

Difference between count (*) and count (col) in the query 1. create the test table declare l_ SQL varchar2 (32767); begin l_ SQL: = 'create table t ('; for I in 1 .. 999 loop l_ SQL: = l_ SQL | 'n' | I | 'number, '; end loop; l_ SQL: = l_ SQL | 'pad

Create or replace function getStrWxr (id in varchar2) RETURN varchar2 AS v_wxrname varchar2 (20 ); BEGIN/* SELECT csrname into v_wxrname FROM workorder_dispatch inner join csr on csr. csrid = workorder_dispatch.csr_id WHERE wo_id = id; */SELECT

One of the database query optimizations is to process more than one million data to increase the query speed: 1. Avoid using the where clause as much as possible! = Or <> operator. Otherwise, the engine will discard the index for full table scanning.

[Oracle] The first thing to note about the maddening ORA-01555 problem is that a ORA-01555 error is a "secure" error that won't cause data loss or corruption, only make the query that receives this error Unable to continue, therefore, in the routine

The oracle job sample declare x number; begin sys. DBMS_JOB.SUBMIT (job => X, what => 'etlrund _ Date; ', nextdate => todate ('2017-08-26 01:00:00', 'yyyy-mm-dd hh24: mi: ss'), interval => 'trunc (sysdate) + 1 + 100', no_parse => FALSE); SYS.

In plsql programming, the variable Declaration creates the first program hello worldbegin dbms_output.put_line ('Hello World'); end;/set serveroutput on; (the command that outputs the statement to the dos window) begin dbms_output.put_line ('Hello

Scenario Description: There are two tables in the oracle database, one of which is tm_bus_realtime_log. The current table only contains data from the previous day. The data volume has millions of data records. There is also a table where the History

[Oracle problem set 2] ORA-01113: file 7 needs media recovery statement: SQL> alter tablespace ts001 offline; SQL> alter tablespace ts001 rename datafile '/home/oracle/db001.df' to '/home/oracle/dbf001.dbf' SQL> alter tablespace ts001 online; error:

Oracle is prone to errors. logical comparison of null and ''1. In Varchar2 format,'' is equivalent to null (no memory is allocated ). [SQL] the result of the statement 'aa from dual where ''is null exists in select.2. logical judgment on null is not