Database Administrator

Without AUTHID CURRENT_USER, The definer permission (definer rights) is executed as the definer identity. With AUTHID CURRENT_USER, the caller permission (invoker rights) is executed as the caller identity. Example: 1. Create two users: xxpo and

Org. springframework. beans. factory. beanCreationException: Error creating bean with name 'sessionfactory 'defined in ServletContext resource [/WEB-INF/config/applicationContext. xml]: Invocation of init method failed; nested exception is org.

I wonder why the ASM instance created with DBCA cannot be started. Manual start SQL> startupORA-01078: failure in processing system parametersLRM-00109: cocould not open parameter file '/opt/Oracle/product/10.2.0/db_1/dbs/init + ASM.

Collection of Oracle 11g statistics 1. Do not use the compute and estimate options for ANALYZE. They have been deprecated. In addition, the statistical information collected by analyze cannot be used by the cost-based optimizer and can only be

In an SQL statement, several subqueries are union. It is okay to execute each subquery separately, but the statement is executed after union, and an error is reported.ORA-00904: "xxx": invalid identifierEach subquery of union must have the same

1: An error occurred while restarting the database today: SQL> startup mountORA-03113: end-of-file on communication channel Take a look at alert. log:...PMON started with pid = 2, OS id = 7359PSP0 started with pid = 3, OS id = 7361MMAN started with

I. Transaction Concept Concept: transactions in databases are logical units of work. A transaction is composed of one or more SQL statements that complete a group of related behaviors, the transaction mechanism is used to ensure that the operations

The period-over-period ratio is the nth month of the year and the nth month of the year, or the nth month of the year. Create a test table, which is assumed to be a sales quantity table: Create table t (dt date, cnt number ); Insert some test data.

1. view the size of all tablespaces SQL> select tablespace_name, sum (bytes)/1024/1024 M from dba_data_files group by tablespace_name; 2. Used tablespace sizeSQL> select tablespace_name, sum (bytes)/1024/1024 M from dba_free_space group by

1. Set this column to null and modify its type (this will cause data loss) 2. The simplest method:Assume that your table is named tab_target.Create table test as select * from tab_target whre 1 = 2;Alter table test modify (col_name number (5

Oracle's rownum is a pseudo-column, and its principle has a lot to do on the net, but we are still very confused. In fact, we just need to understand its principle. What's important is to use it, therefore, we only need to ensure that we do not make

Combination of range partitions and hash partitions or list partitionsSyntax: PARTITIONBYRANGE (column_name1) SUBPARTITIONBYHASH (column_name2) SUBPARTITIONS number_of_partitions ( PARTITION part1 value less than (range1 ), PARTITION part2

If you have not installed or used sqlite, you can use SQLite3 for installation and basic operations. 1. Create a database test. db Cd ~ / Sqlite3 test. db In this way ~ /A database file test. db is generated under the directory. 2. Create a table

The database initialization parameters used for Oracle Database startup are usually obtained using the show parameter command in sqlplus. However, only some public parameters and modified hidden parameters are shown here. Oracle also has a number of

Differences between Oracle row triggering and statement triggering 1. the row trigger has a for each row clause. The statement trigger does not have a for each row clause.2. the row trigger can have the when as the trigger limit. You can use new/old.

Oracle spatial data SQL query related instances -- Select dlbm, dlmc, trim (zldwdm) as zldwdm_1 from gzdt where nvl (zldwdm, 'T') = 'T' or zldwdm = '';Update gzdt set ZLDWDM = '000000' where nvl (zldwdm, 'T') = 'T' or zldwdm = '';Commit;Delete from

Transaction, transactions Transaction Features (isolation level) A: atomicity. Transactions are an inseparable unit. C: consistency. transactions must change the database from a consistent state to another consistent state. (For example, transfer) *