Oracle

ProgrammersThe focus is on the logical structure of the program, and the main purpose for the developer is to interact with the data.The reason for explaining user management is mainly to explain DCL, Data Control language, grant and revoke.Such two

First, IntroductionThe importance of Oracle databases in system operations is self-evident, and the knowledge of operating systems and databases is deepened through familiarity with the installation of Oracle. Linux installation Oracle early

PL/SQL Exception handlingException handling when the input number is not in the casedeclare-- definition v_ename emp.ename%type;begin--Selectfromwhere Empno = &gno;dbms.output.put_line (' name:'| | v_ename); Exceptionwhen no_data_found

1. Reduce I/O operations:SELECT count ( case if empno>then 1 END) C1, Count empnothen 1 END) C2 from EMP;2. Access via ROWIDSELECT ROWID,emp.* from empWHERE Rowid=chartorowid (' aaahw7aabaaamuiaaa ')3. Use index unique scanSELECT empno,ename

What is the index?(1) is a mechanism for quickly querying the contents of a table, similar to the directory of the Xinhua dictionary(2) apply to one or more fields in a table, but when stored, independent of the tableWhy do you use an index(1)

Based on the relational database SQL Server has been contacted, the database, tables, records, table additions and deletions to the operation of these basic concepts have been understood.Oracle is an object-based relational database, and Oracle also

First, Sqlplus, the direct use of Desc[ribe] tablename can be.Second, when external application calls view the table structure in Oracle, you can only use the following statement instead:1. See field names and data typesSelect * from cols

1 definition: Runtime variables allow us to interact with SQL statements, allowing us to dynamically pass parameters when executing SQL statements2. Syntax:&varname3. run-time variables can appear in any locationFor example:Select &colname1,&colname2

What is a trigger "Trigger"?Different DML (SELECT/UPDATE/DELETE/INSERT) operations, triggers can be intercepted, the operator of the conditions can operate the base table, conversely, the base table is not operational. Similar to the filter in

Direct Examples:1.CREATEuser username identified by password default tablespace table space name;Grant Alter,delete,update,insert,select on table name to user name;2. Directly with the above user login Plsql (for example, the user name is User1,

There are many ways to implement paging, but it is common to display paging through SQL.Here is the introduction of MyBatis to implement the Oracle paging: (PS: Different database of the wording of the difference)One, paging data :1

Oracle's concurrency technology allows a large task to be broken down into multiple small tasks that are done together by multiple processes. Reasonable use of concurrency can make full use of system resources and improve efficiency.One, the type of

Query the current process of the database and the number of connections to the session, the number of concurrent connections and the status of the session and so on, you can refer to the next ha, hope to help you1. Query the number of connections to

Multi-table queries , including equivalent connections , non- equivalent connections , outer joins , self-joins .internal connections , including equivalent connections and non-equivalent connections .Cartesian set of employee table EMP and

The current summary of the statement, in view of the data connection is very useful, after writing the program while testing the code side to see the release of database connections to help optimize the analysis of a robust system program.1.SQL code1

---正在执行的select a.username, a.sid,b.SQL_TEXT, b.SQL_FULLTEXT  from v$session a, v$sqlarea b where a.sql_address = b.address ---执行过的select b.SQL_TEXT,b.FIRST_LOAD_TIME,b.SQL_FULLTEXT  from v$sqlarea bwhere b.FIRST_LOAD_TIME between ‘2009-10-15/09:24:47

background :Development language: C #Development tools: VS2010A-party Oracle database: Chinese Character setB-party Oracle database: English Character setDelivery Mode: WebService method (take data, and put the extracted data into the DataTable,

1. Check the location of the table space on the physical disk, and pay attention to the login using SYSDBA's account.SELECTfile_id file_name round/(1024x768 * 1024x768 0 from ORDER by2. The table space that needs to be expanded is Dw_stg_tbs, the

Today I learned the wording of Oracle's package and then encountered a problem. Both the package declaration and the package body are correct, but the error is executed: Object Omgmig.test_package is invalid.This is an error SQL, it looks normal,

1. View All Users:SELECT * from Dba_users;SELECT * from All_users;SELECT * from User_users;2. View user or role system permissions (System permissions that are directly assigned to a user or role):SELECT * from Dba_sys_privs;SELECT * from