how many dbas can llc have

records returned must be unique, such as the user ID. Misuse of distinct will cause unpredictable errors, such as multi-table connection queries.V. Rational creation of indexesThe last point is to reasonably create the table index, simply put, if there is a 100,000 records of the data table, you may often query such information: "One of my customer information in this table?" ”。 If an index is used, retrieving this customer information will be very rapid, otherwise the database optimizer will c

building composite indexes that make it easier to hit index overlays in complex SQL. such as the following: 1 SET STATISTICS IO on 2 SELECT orderstatus, Processstatus, sendticketcity, Flightagency, Eticket, OrderID 3 from Dbo. Orders WHERE orderstatus= ' P ' and processstatus= ' 1 ' and Sendticketcity=1 Then continue to select a few indexes to aim at ... In general, indexes that cover between 1 and 2 columns are called small indexes. 1 DBCC SHOW_STATISTICS (o_orders,idx_eid_orderdate) 2 DBCC

Tags: default DEX permission statement rod Gem Oracle Max StepSteps:1. Create a temporary table spaceCreate temporary tablespace cindex_temp tempfile '/u01/oracle/app/oradata/mytablespace/cindex_temp.dbf ' size 1024m Autoextend on next 100m maxsize 10240m extent management local;2. Create a table spaceCreate tablespace cindex logging datafile '/u01/oracle/app/oradata/mytablespace/cindex dbf ' size 1024m autoextend on next 100m MaxSize 10240m extent management local;3. Create a user and specify a

We have published three articles in the first, second, and third articles in one of the basic questions and answers for Linux interviews, which are well received by readers. At the same time, we have received feedback. Some readers hope that this

DBA manages all the data in the database. However, it is not convenient to use the Administrator identity for some data operations due to audit or other reasons, however, you do not know the user password of the Oracle user, because the Oracle user

　　 During the development process, you may need to find out when the database is created, how many tables are in the database, how long the Stored Procedure looks, and so on, today, I will summarize some of the Database Engine stored procedures and

What is an execution plan? The information on which the execution plan depends. An execution plan is a query solution made by the database based on the statistics of SQL statements and related tables. This solution is automatically generated by the

[51CTO external headlines] We once discussed "What role does NoSQL play in our work ?" We have also raised 101 questions about how to choose a NoSQL database. We even held an online seminar to thoroughly analyze what SQL, NoSQL, or applications can

Many server administrators know that the MySQL database management system (RDBMS) is a highly flexible software block with a wide range of startup options that can be used to modify related behavior. However, most people are not aware that standard

Grantselectanydictionarytoscott; createtablet1asselect * fromemp; insertintot1select * fromt1; -- query the user to view scot Grant select any dictionary to scott; create table t1 as select * from emp; insert into t1 select * from t1; -- query the

BKJIA: From DB2 9.7, you can use the following query to check indexes not used in DB2: SELECT INDSCHEMA, INDNAME, TABNAME      FROM SYSCAT.INDEXES   WHERE  LASTUSED = '01/01/0001';  The LASTUSED column tells you the last access time of

DBA manages all the data in the database, but it is not convenient to use the Administrator identity for some data operations due to audit or other reasons, but you do not know the convenient Oracl DBA manages all the data in the database, but it is

Directory1. What is an execution plan? The information on which the execution plan depends.2. Unify SQL statement writing to Reduce parsing overhead3. Reduce SQL statement nesting4. Use "temporary table" to save intermediate results5. The SQL

Oracle Database 10g audit captures user behavior at a very detailed level, which can eliminate manual, trigger-based audit. Assume that user Joe has the permission to update the table and updates a row of data in the table as follows.

1. Backup is more important than anything We need to know that the system is always going to crash, there is no valid backup just waiting for the day to die! I often joke that the only thing that will wake the DBA in a dream is that there is no

After a few years of Oracle's book, I have a little experience with different books. Many friends let me recommend some Oracle books, below I will say my opinion.In fact, at different stages, different books will have different effects on you,

Here, without talking about the big things, like knowing the whole IT environment, assuming you already know that, then you have to deal with these living database. Here is a summary of some general ideas to face a full first database, so that you

1 Running Sqlplus Tools Sqlplus 2 The default identity of the OS Connection /As Sysdba 3 displaying the current user name Show user 4 go directly to the Sqlplus command prompt Sqlplus/nolog 5 connecting at the command prompt with OS

DBA View Serial number 1 Dba_data_files Information about the database file 2 Dba_db_links All database links in the database 3 Dba_extents Include all partitions in

1. Abbreviations 1) sndcp: subnetworkdependence converage protocol, subnet-related aggregation Protocol 2) nsapi: Network Layer Service Access Point identifier. The identifier of the network layer service access point is actually an index of the PDP context of the service using the sndcp layer, the Service Access Point provided by sndcp to the upstream layer; 3) SAPI: the service access point provided by LLC to the upstream Layer 3）Qos：quality ofservi