Tag：oracle
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Graphic tutorial of Oracle 11g database deployment
Novice Oracle 11g deployment Oracle database, also known as Oracle RDBMS, or Oracle for short. Oracle is a relational database management system. It is a leading product in the field of database. It can be said that Oracle database system is a popular relational database management system in the world at present. The system has […]
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Detailed explanation of rownum usage in Oracle Database
Summary of rownum usage in Oracle! For the rownum problem of Oracle, many materials say that >, > =, =, between And, you can only use the above symbols (<, < =,! =), not >, & gt; =, =, between.. And will prompt SQL syntax errors, but often a record cannot be found, and seemingly […]
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Process diagram of CMD operating Oracle data import library
1. In the CMD window, log in to the administrator user: sqlplus sys/1 as SYSDBA 2. Create a new user and authorize the user: (1) Create user —Create the user create user Helq3_Pro identified by “1” default tablespace MOF temporary tablespace TEMP profile DEFAULT; (2) Authorize users SQL> grant dba to helq3_cpbgt_20200714 with admin option; […]
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Oracle database cursor connection beyond solution
Oracle database is suddenly disconnected. Once checked, the number of cursors is exceeded. 1. View the number of cursors show parameter open_cursors 2. Modify the number of cursors alter system set open_cursors = 10000; 3. Get the number of open cursors select o.sid, osuser, machine, count(*) num_curs from v$open_cursor o, v$session s where user_name = […]
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How Oracle sets the tablespace data file size
The default maximum size of Oracle data file is 32g. If the data file is larger than 32g, it needs to be set at the beginning of database creation.Table space data file capacity and DB_ BLOCK_ Size is related. When the database is initially built, DB_ BLOCK_ The size should be set to 4K, 8K, […]
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Oracle realizes data synchronous migration through logminer
Write in front Recently, we are studying how to realize the data synchronization between Oracle databases, and there are really few materials on the Internet. The best Oracle database synchronization tool is GoldenGate, which is charged. Is there any good way to synchronize Oracle data? Yes, logminer is used to realize synchronous migration of Oracle […]
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The use of SQL windowing function in Oracle Database
Windowing function: before the emergence of windowing function, there were many problems that were difficult to solve with SQL statements, many of which were completed through complex related sub queries or stored procedures. In order to solve these problems, the ISO SQL standard added windowing function in 2003. The use of windowing function makes these […]
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How Oracle uses pl/sql to debug stored procedures
The debugging process is very important to find a bug or error that has been stored. As a powerful commercial database, Oracle can save more than 10 lines or thousands of lines if it has been stored too much. Bugs are inevitable. If it has been stored for thousands of lines, it is also very […]
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Detailed explanation of Oracle debugging stored procedure
If Oracle stored procedures are complex and it is difficult for us to locate errors, we can use the debugging function of stored procedures Let’s take a simple stored procedure as an example, that is, the last stored procedure (proc_test) 1. Create a stored procedure before finding us in the procedures file of the database […]
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Oracle date operation statement summary
1. Query the relevant time of the current year, month and week 1.1. Query current year SELECT TO_ Char (sysdate,’yyyy’) as year from dual– query the current year SELECT TO_ Char (sysdate,’yyy’) as year from dual– query the last two digits of the current year SELECT TO_ Char (sysdate,’yy’) as year from dual– query the […]
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A former Oracle Engineer posted a “slander” on MySQL: “terrible! Strongly recommend Postgres”? The truth is surprising
Recently, Oracle engineers who are about to leave and switch to Google posted an article on their blog to “attack” mysql. He claimed that PostgreSQL is a better choice for open source RDBMS. “MySQL is a ‘pretty bad’ database, and you should strongly consider using Postgres”. It is reported that the engineer’s name is steinar […]
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Why is the data import of Oracle and MySQL so different
Some friends often ask me about some database problems, and I noticed a very interesting phenomenon. All data import problems are basically Oracle problems, and MySQL problems don’t exist once in my mind. I can’t help thinking about this unexpected problem: Why do Oracle encounter many problems when importing data? Let’s sort out this problem […]