Oracle

Copy the statistics from the production library to the development library for tuningBefore confirming the execution plan1. Import the optimization statistics of the production environment into the development environmentdo not collect optimization

2.TRUNC ( for number)The TRUNC function returns the processed value, and its working mechanism is very similar to the ROUND function, except that the function does not make the corresponding rounding selection processing of the specified fractional

Storage structure of the databaseDatabases are primarily used to store and retrieve related information, and the Oracle database contains logical and physical structures.Physical structure refers to a real storage unit, consisting of a set of files,

Check the Select Userenv (' language ') from dual first, view the Oracle character set,$ sqlplus/nologSql> Connect sys/oracle as SysdbaSql> StartupHow to set the encoding for an Oracle database (ZHS16GBK) modified to UTF8sql> shutdown immediate;sql>

Because Plsql does not support 64-bit Oracle clients, PLSQL must use Oracle's 32-bit instanclient package. Unzip and place a directory, for example: D:\Oracle\instantclient_10_2PS: 10g 32-bit instantclient package can also be connected to the 11g

The following test begins with the new features of Oracle 11g truncate enhancements and delay segment space creation. Oracle starting with 11g, when a user creates an empty table, the segment and space are not allocated first, only when the first

"One" configuration ODBCWin7: Control Panel (View by: small icon) → administrative tools → data source (ODBC)Under the ODBC Data Source Administrator panel, under Default User DNS, click the Add buttonSelect "Oracle in Oraclient11g_home1" ( provided

Recently do data analysis, need to use the cumulative function, found that the powerful Oracle really, with over (order by field)Example:The last column in the data table is the cumulative effectAccumulate sql:Select T.acc_pedal_pos,count (*)

Users who are always concerned about Oracle database know that Oracle Performance optimization guarantees the robustness of Oracle database. Here are two principles to note.Principle One: Note the connection order in the WHERE clause:Oracle uses a

With the knowledge of more and more, but also more and more found their own shortcomings, simply record the learning of the knowledge bar.Although Oracle is used in the project, it is not really a sufficient application for Oracle, for example, if I

Select Upper (' Testmyname ') from dual; --Convert to uppercaseSelect lower (' Testmyname ') from dual; --Convert to lowercaseSelect Upper (substr (' Testmyname '), 5) from dual; --intercept myname and convert to uppercaseSelec InStr (' Testmyname ',

Oracle 11g 64-bit installation sqldeveloper is not open for workaround:1. Download the corresponding version of Sqldeveloper to the official website.2. Find the F:\app\Administrator\product\11.2.0\dbhome_1\sqldeveloper overlay under the

First, the functionA function is similar to a stored procedure and is also a named Pl-sql block stored in a database. The main feature of a function is that it must have a return value. The return type of the function is specified by return.

Why should I use it?After reviewing some information, I got the conclusion that Relational databases are set-oriented, and cursors are row-oriented, and cursors can perform the same or different operations on each row in the extracted collection (

As with all the tips, the last move will go back to the beginning, and finally we'll talk about whether or not you need to index, perhaps a full table scan faster.In most cases, full table scans may result in more physical disk input and output, but

How to start Scott user in Oracle 11gR2, 11gr2scott How to start Scott user in Oracle: In Oracle11gR2 (g stands for 'network') the Scott user in the database is locked during installation. When installing Oracle, you can directly unlock the user. If

Oracle single row subquery Subqueries can contain SELECT statements in SELECT, UPDATE, and DELETE statements. The internal SELECT statement result can be part of the Condition Clause in an external statement,It can also be used as a temporary table

Trigger 4 (learning notes), trigger learning notesREFERENCING clause:Use ": new. field "or": old. if the field is not clearly marked, you can use the REFERENCING clause to set the alias for the two identifiers. For example, you can set ": new" to

PLSQL _ Statistics Series 3 _ statistics are migrated in different databases (case studies), and plsql statistics 2014-01-05 Created By BaoXinjian I. Summary Because the system is upgrading or cloning data for migration, it may cause data

Oracle ORA-00988 missing or invalid password error, ora-00988invalid When setting the password for the database instance, be sure not to start with a number, otherwise you will encounter a ORA-00988 missing or invalid password (password missing or