how to tune sql query in oracle

Tags: Oracle where generalSQL query statement describes the--select statement1. Simple SELECT query statement1.1 Check.Sql> select * from EMP;1.2 Check ListSql> select Empno,ename from emp;1.3 Related queriesSyntax for Oracle:Select a.*,b.* from emp a,dept b where a.deptno=b.deptno;General Syntax:Select a.*,b.* from emp a joins Dept b on (a.deptno = B.deptno);1.4

will use the memory of the sort_area_size. The optimization of this memory is also very important.4. The Order by statement is added to the index column, preferably the primary key PK. SELECT Dept_code from DEPT ORDER by Dept_type (inefficient) 5. Avoid using resource-intensive operations:SQL statements with distinct,union,minus,intersect start the SQL engine to perform the resource-intensive sorting (sort) function. Distinct requires a sort operati

for language settings. If the character set is zhs16gbk, The nls_lang can be American_America.zhs16gbk. Involves three character sets, 1. Character Set on the El server side; 2. Character Set of oracle client; 3. dmp file character set. During data import, the three character sets must be consistent before the data can be correctly imported. 2.1 query character sets on

using Oracle parallel queries to play the power of multiple CPUs2006-07-05 07:00 Author: Source: BLOG Editor: Ark the installation of more CPUs in a separate server is a current trend. With symmetric multi-processor (SMP), it is not surprising that an Oracle server has 8, 16 or 32 CPUs and several gigabytes of RAM. Oracle has been following the pace of hardware

there are usually several ways to tune a database: 1) Manual tuning. The main reliance on people, inefficient, requiring the operator to fully understand the principle of common sense depends on, but also the application, database management system, operating system and hardware have a broad and deep understanding. 2) Case-based tuning . This paper summarizes the recommended configuration val

. Currently, this parameter is not supported.And 17.3.2.1. rules and restrictions on using Stored Procedures To use stored procedures in hibernate, you must follow some rules. stored procedures that do not follow these rules will not be available. If you still want to use them, you mustSession. Connection ()These rules apply to different databases because database providers have different stored procedure syntax and semantics. Query of stored proce

The first thing to note is that the content of this article is not how to tune SQL Server query performance (about which you can write a book), but how to leverage the set STATISTICS IO and set STATISTICS in SQL Server query performance tuning Time these two frequently ignor

cannot create a database structure.Connect: A user with connect permission can only log on to Oracle, not create an entity, and cannot create a database structure.For normal users: Grant Connect, resource permissions.For DBA administration users: Grant Connect,resource, dba authority.System Permission Authorization command:System permissions can only be granted by the DBA User: sys, system (only two users at the beginning)Authorization Command:sql> G

number of CPUs in the server, it automatically assigns the appropriate number of child processes to increase the response time for parallel queries. Of course, there are other external factors, such as table partitioning and the layout of the disk input/output subsystem, but setting the parallel_max_servers parameters according to Cpu_count will give Oracle a reasonable basis for choosing the degree of parallelism. Because Oracle's parallel operatio

Tags: calculate high-precision modified address EFI struct arithmetic uname table structureSQL queries and SQL functions 　　This chapter aims 　　　　Understanding Oracle Data Types Understanding Data Definition Languages and data manipulation languages Understanding Transaction Control Languages and Data Control languages Mastering SQL Operators and

and 123456 passwordC:\>sqlplus scott/123456Exit Sqlplus Environmentsql:\>exit;Query all tables under the Scott userSELECT * from tab;Query who the current user isShow user;Set the displayed column width (character, date), 10 characters wide, a for the character typeCol ename for A12;A12: Indicates a display width of 12 characters, a case insensitiveExecutes the most recent

Mysql oracle and sqlserver query instance resolution by PAGE, oraclesqlserver Recently, I have made a simple research on the paging query of oracle, mysql, and sqlserver2005 data, and posted their query statements for you to learn ..... (1) mysql paging

: = Fun_creategeometry ( WKT = WKT, Srid = Srid ); INSERT into map_user_8332 (OBJECTID, SHAPE) VALUES (OBJECTID, V_return); END Addnewpoint; Call the stored procedure to create the geometry, noteThe Srid must be consistent Called in Oracle SQL developter: DECLARE OBJECTID number; WKT VARCHAR2 (200); SRID number; BEGIN OBJECTID: = 100; WKT: = ' point (118.731963311458 32.0661417793197) '; SRID: = 4326; Ad