Tag：oracle
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Time：2020-1-18
Oracle can’t use the solution of EM, the details are as follows You can’t log in to EM and execute EMCA – config dbcontrol dB. You don’t know that the port number of 1522 is always the default port number, but Google will start from the second step below… (my monitor is OK) 1. Open […]
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Time：2020-1-17
To uninstall Oracle 11g: 1. First turn off all Oracle related services, and then find the Oracle uninstall program universal installer: Then click uninstall product, then click expand all to uninstall all applications except the main directory, and then click display empty directory to delete the main directory. 2. Delete the registry: Press the windows […]
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Time：2020-1-15
Preface When the database is transmitted across the network, you can perform the import operation by using the network link parameter. The import operation will use the database link and does not need to generate the dump file. The operation steps are as follows: 1. Create a data link in the target database that is […]
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Time：2020-1-10
Dear database administrators and engineersHello, everyone. Thank you for your support for dbask. Dbask is an open, mutual aid and convenient database Q & a community. You can ask questions on dbask if you encounter any database problems. The platform certified technical experts can answer them online for free, and finally file them into an […]
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Time：2020-1-10
1. create table create table test_1(num number(2) not null,name VARCHAR2(20) not null,primary key(num)); Create a table with two fields, Num and name, which are set to be non empty, and num is set to be the primary key. When creating a table, there is often an error message of “missing left bracket”. It is estimated […]
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Time：2020-1-9
1.TRUNC（for dates） The date value truncated by the TRUNC function for the specified element. The specific syntax format is as follows: TRUNC（date[,fmt]） Among them: Date a date value FMT date format, which will be truncated by the specified element format. Ignore it and cut it off by the latest date Here is the usage of […]
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Time：2020-1-8
First open CMD to execute orapwd file=C:\app\PWDorcl.ora password=orclorcl C: \ app \ pwdorcl.ora is the path file you want to store Password = orclorcl is the password you want to change Then enter, and a file will be generated under this path. Replace this file with your local Oracl password file. The sys and system […]
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Time：2020-1-6
Install MySQL 5.7.17 as follows: 1. Download http://www.codeyyy.com/linux/149-150-153.html 2. Upload and decompress tar -xvf mysql-5.7.17-linux-glibc2.5-x86_64.tar.gz 3. Create a new MySQL directory mkdir -p /usr/local/mysql/data mv mysql-5.7.17-linux-glibc2.5-x86_64/* /usr/local/mysql/ 4. Add user group groupadd mysql 5. New user useradd -g mysql -d /usr/local/mysql mysql 6. Change MySQL directory permission chown -R mysql.mysql /usr/local/mysql/ 7. Initialize the database […]
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Time：2020-1-4
Oracle case conversion function Lowercase to uppercase upper Capitalize to lowercase lower Example: select lower(ename) from emp; select upper(ename) from emp; –Include letters (upper and lower case) Select case when regexp_like (‘123 ‘,’. ([A-Z] + | [A-Z]) ‘) then’ contains the letter ‘else’ and does not contain the letter ‘end from dual’; –Include lowercase letters […]
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Time：2020-1-2
According to the survey, SQL is the second largest programming language at present. It has been playing an important role for more than 40 years since its birth, with 50% of developers using SQL. Although it is widely used, the quality level of SQL is not satisfactory. According to experience, 80% of the database problems […]
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Time：2020-1-2
Oracle sqlldr importing a date column instance 1. LOAD DATA INFILE * INTO TABLE test FIELDS TERMINATED BY X’9′ TRAILING NULLCOLS ( c2 “upper(:c2)”, c3 date “yyyymmdd”, c1 “SEQ_test_c1.nextval” ) BEGINDATA AAAAAAAAAA 20051201 BBBBBBBBBB 20050112 CREATE TABLE TEST ( C1 VARCHAR2(10 BYTE), C2 VARCHAR2(20 BYTE), C3 DATE ); CREATE SEQUENCE VV_USER.SEQ_TEST_C1 START WITH 0 MAXVALUE […]
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Time：2020-1-1
A detailed explanation of Oracle’s tablespace instances Query tablespace Select upper (f.tablespace “name)” tablespace name “, D. Tot “table space size”, D. Tot ﹐ gross ﹐ MB – f.total ﹐ bytes “used space”, TO_CHAR(ROUND((D.TOT_GROOTTE_MB – F.TOTAL_BYTES) / D.TOT_GROOTTE_MB * 100, 2), ’990.99′) “usage ratio”, F. Total_bytes “free space (m)”, F. Max? Bytes FROM (SELECT TABLESPACE_NAME, […]
