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DB version: Oracle database 11g Enterprise Edition release 11.2.0.2.0- 64bitORACLE11G adds new features for virtual columns, as described below:1> can only create virtual columns on the heap organization table (normal table), cannot create virtual columns on index organization tables, external tables, temporary tables2> Virtual column cannot be lob or raw typeThe value of the 3> virtual column is not real a

the operation, and not jump to other interfaces. This will use one of the struts2 's actions to jump to the function of another action, that is, after the action of the second action is completed, jump to the action of the first action. In this, Struts.xml should be configured like this:End of background. Finally, the front end is displayed. I am from the background to the unread data and read data (in the database Admin_flag equals 0 and 1) are queried, in the front-end need to classify displa

reserved Records is 100Sql>set History 3;7. View Hist retained RecordsSql> hist list;1 show Con_name2 show parameter version;3 Show hist;Description: The number of records retained is calculated by command rather than by line count.8. Run the specified recordSql> hist;1 Select sysdate from dual;2 show Con_name3 Select date from dual;Sql> hist 2 run;Con_name------------------------------Cdb$root9. Edit the previous commandhist 1 edit;Description: You can operate like Linux VI and edit the retain

has been strengthened again, we can not set the NOT NULL here, greatly reducing the possible error operationSee the following experimental processCREATE table T, where more than 1 million rows of data.Sql> Select COUNT (*) from T; COUNT (*)---------- 1454256Add a column directly to the table (not set NOT NULL)Sql> ALTER TABLE t add MRDAI1 number default 10000; Table altered. elapsed:00:00:00.03The speed is swift. And, of course, as in 11G.After the setting is complete, if it is a newly inser

Oracle transaction features a transaction refers to a complete logical process composed of a series of database operations. For example, the bank transfers, deducts the amount from the original account, and adds the amount to the target account. The sum of the two database operations constitutes a complete logical process and cannot be split. This process is called a transaction and has ACID properties. 1:

Why should we discuss this issue? It is rooted in history. Let's start with Oracle 10 Gb. Before 11G, if you want to add a new column to a large table and the new column has a default value, if you want to use alter table xx add xx_1 number default 1000; this type of statement settings will be very handy! Its action is to add a column and update the column. If the table is very large, a very large transaction will be generated. Because it is a ddl ope

Oracle 9i has achieved new breakthroughs in cluster technology, high availability, business intelligence, security, and system management, and its features include the following.1.4.1 Cluster TechnologyThe principle of clustering is shown in Figure 1.2.1.4.2 Online analytical processing, data mining and analysis technology1. What is online analytical processing2. What is a data warehouse3. What is data mini

Tags: Oracle online convertBefore the Oracle12.2 version, if you want to convert a non-partitioned table to a partitioned table, there are several ways to do this: 1. Build the partition table and insert the data into the partition table with the INSERT into SELECT, 2, use the method of online redefinition (dbms_redefinition). Their currency is: the first method, if the table has frequent DML operations, especially the update operation, you need to st

Tags: style blog http io ar using SP on dataAtomic NatureA transaction is a complete operation. The steps of a transaction are non-divided (atomic), either executed or not executed. --Create TABLE Account_money ( ID number (4) Not NULL, name varchar2 (4) isn't null, money number ( 5,2) not NULL);--Add a CHECK constraint ALTER TABLE Account_money add constraint Ck_money check (money>=0);--Add data to Zhang San this account insert into Account_money (ID, name, money) VALUES (1001, ' Zhang

Overview: In an Oracle database, partitioning (partitioning) allows very large tables (table) or indexes (index) to be decomposed into small manageable blocks (pieces). These blocks are called partitions (partitions). Each partition must have the same logical structure, such as column names, data types, constraints, and so on, but each partition can have its own independent physical structure.Benefits of Partitioning:1. Increase the availability of:2.

------------------------- ------------------------- -------- ---------- -----------P_andy idx_pandy_id unusable 0 1--Rebuilding the indexsql> ALTER index IDX_PANDY_ID rebuild;Index altered.--View index statusSql> Select Table_name,index_name,status,blevel,leaf_blocks from user_indexes where index_name = ' IDX_PANDY_ID ';table_name index_name STATUS Blevel leaf_blocks------------------------- ------------------------- -------- ---------- -----------P_andy idx_pandy_id VALID 0 1--Truncate multiple

(2, Seq_session.nextval); SQL>Select* fromSCOTT.GTT; ID Seq_number---------- ----------1 3 2 4SQL>Continue the test.--end of session, sequence value will be resetSql>conn tiger/Tigersql>drop synonym GTT; SQL>drop synonym seq_session; SQL>create synonym GTT forSCOTT.GTT; SQL>create synonym Seq_session forscott.seq_session; SQL>Select* fromgtt;no rows Selectedsql>sql> INSERT INTO GTT values (1, Seq_session.nextval); sql> INSERT into GTT values (2, Seq_session.nextval);-I

Prior to the Oracle 12c version, the VARCHAR2 and NVARCHAR2 data types had a maximum length of 4000, with the extended maximum of 12c versions supported to 32767, or 32KB, and parameter Max_string_ The size is the maximum length of the extended data type that controls the extended datatype: Standard: Represents the length limit before 12c, that is, VARCHAR2 and NVARCHAR2 4 is 4000 Bytes,raw is 2000, and the system is standard by default;

Five types of policies, column-related policies, and column masks make VPD a more powerful tool in the DBA's security toolbox The Virtual Private database (VPD), also known as fine-grained access control, provides powerful row-level security features. It was launched in Oracle8i and has been widely welcomed and used in a variety of applications, from educational software to financial services. VPD's approach is to provide a partial view of the table

Tags: Oracle database 12cThe thousands of expected Oracle In-memory options are included in the version of Oracle 12.1.0.2 . Now that Otn has provided the download to begin with, the current major version is the Linux x86 and Solaris Platform, the software installation process is similar to the previous version, this article begins with a new installation,DBCA Af

> alter session set optimizer_use_invisible_indexes = true;Sql> SELECT * FROM test where object_id = 10;Run a plan----------------------------------------------------------Plan Hash value:255872589-----------------------------------------------------------------------------------------------| Id | Operation | Name | Rows | Bytes | Cost (%CPU) | Time |-----------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 1 | 100 | 2