Oracle

[Oracle] transaction isolation level (implementation of Oracle) 1. Read committed (Default) the lowest isolation level of Oracle is Read committed, which has the following features: this is the default transaction isolation level of ORACLE. Each

In Oracle, changing the CHAR fields in all tables under the table field type tablespace to VARCHAR2 in batches is too many data table fields. It is too troublesome to change the fields one by one, so I thought of the following method: [SQL] DECLARE

Weibo database design part functions table creation design Users user registration information table description field name type null other Users IDuser_idnumber (8) No primary key user email user_emailvarchar (40) No user password

Oracle materialized view creation report ORA-00942 error solution in Oracle10g Database, a materialized view made a simple Condition Clause modification, delete and re-build, but, it is not created successfully, reported ORA-00942 table or view does

In summary, it took me one night to install oracle on ubuntu. I checked a lot of information for the first installation. after a variety of problems, I finally finished it. now I will share some installation steps and installation experience. You

Oracle over Grouping sorting explains oracle's analysis function over and window function eg: Related Analysis: table t_pi_part field id code namevalue 1 222 avalue 2 222 bvalue 3 333 c add a row mark to the part code with the same code and sort

By default, the date and time formats displayed by RMAN are displayed only on the RMAN backup and recovery page, but no specific time is specified. Sometimes you need to view the specific time, for example, to view multiple Incarnation events of the

Oracle flashback searches for the current scn value 1. find the current scn value SELECT dbms_flashback.get_system_change_number from dual; assume the returned value is 140856480 2. count or view the record of the current scn value SELECT count (*)

Oracle numeric functions use oracle SQL to perform operations on numbers: rounded up, rounded down, N decimal places retained, rounded down, and number formatted (rounded down ): select floor (5.534) from dual; select trunc (5.534) from dual; both

Concepts that must be mastered before the Oracle architecture for beginners, before learning about the Oracle architecture, you must master the following two basic concepts: databases and instances. 1. database is a collection of data. Whether the

We know that Oracle has a very small division of Oracle permissions. Therefore, if you do not have the required permissions, errors may occur. only the user sys generated by default after the database is created has the highest permissions and

Use of Table functions in Oracle -- 1. table and array use example create or replace type t_test as object (id integer, rq date, mc varchar2 (60); create or replace type t_test_table as table of t_test; create or replace function f_test_array (n in

Diagnose and solve row chained and migrated Listing Chained Rows of Tables and Clusters1.execute the UTLCHAIN. SQL or UTLCHN1. SQL script. the script is located at: @ oracle_home \ rdbms \ admin \. The script content is rem $ Header: utlchain. SQL 07

The blob type in the oracle database can be directly converted to varchar2 if there is no data. If you have tried it, you can also change it. However, it is generally only possible to modify the data, which is troublesome and cannot be changed

At the same time, the efficiency of querying the maximum and minimum values sometimes needs to query the maximum and minimum values of some data at the same time. How can we get the results as quickly as possible? We know that the index has already

Oracle Partition Summary This article describes the concepts and operations of Partition tables from the following aspects: 1. table space and Partition Table concept 2. table Partition Function 3. advantages and disadvantages of Table Partitioning 4

Method 1) reduce the use of public synonyms in SQL, and specify the schema name in SQL. Large OLTP systems where users log in to the database as their own user ID can benefit from explicitly qualifying the segment owner, rather than using public

Oracle data is transferred from one user to another. export the available command exp, similar to the following exp da1/da1 @ ORCL file = E: \ da1.dmp log = E: \ da1.log da1 is the user name, And the backslash is the password, @ is the database

In oracle's to_char, fm SQL> select '| to_char (5, '000000') |' from dual; the result is: | 5 | SQL> select '| to_char (5, '000') |' from dual; the result is: | 005 | SQL> select '| to_char (-5, '000') |' from dual; Result: |-005 | visible: the

Using resource_limit and profile to limit user connection to database performance is an eternal topic, that is, how to use fewer resources to achieve more efficient performance. The Oracle system parameter RESOURCE_LIMIT is a parameter used to