Oracle

1. What is registration? Registration is to register the database as a service to the listener. The client does not need to know the Database Name and Instance name. It only needs to know the service name provided by the database to external users

During database operations, we may encounter this situation, and the data in the table may be repeated, causing a lot of inconvenience during database operations, so how can we delete the useless data?The deduplication technology can provide a

A table connection refers to the association between tables in an SQL statement to retrieve relevant data from one or more tables, in general, the table and table connections can be divided into four types: equal connection, external connection,

Common dump commands in Oracle for future reference. 1. Memory Dumps 1). Global AreaAlter session set events 'immediate trace name global_area level n ';1 Including PGA2 contains SGA4 include UGA8 contains indrect memory 2). Library CacheAlter

The Oracle database cannot be connected, and related errors are prompted.OERR: ORA-12519 TNS: no appropriate service handler foundClient Connection intermittent failure, error ORA-12519Cause: the listener cocould not find any available service

View all tables in Oracle:Select * from tab/dba_tables/dba_objects/cat;View the table created by the user:Select table_name from user_tables; // The table of the current userSelect table_name from all_tables; // tables of all usersSelect table_name

Today in the data export, because the user name password is a special character, so encountered the error code: "EXP-00056: encountered ORACLE error 12154", online search for the reason, the quotation marks must be used for expansion, but the

1. OriginWhen the oracle database field value is less than 1 decimal point, the char type is used for processing, and the 0 before the decimal point is lost.For example, 0.35 is changed to. 35. 2. Solution: Use the to_char function to format the

Remove line breaksUpdate zhzl_address t set t. add_administration_num = replace (t. add_administration_num, chr (10 ),'');Remove carriage returnUpdate zhzl_address t set t. add_administration_num = replace (t. add_administration_num, chr (13

You can use the following SQL statement in PL/SQL to query which tables in the current database are locked and which users are locking these tables: SELECTA. OWNER, -- user to which the OBJECT belongsA. OBJECT_NAME, -- OBJECT Name (table name)B.

ORACLE locks have the following modes:0: none1: null2: Row-S Row sharing (RS): Share table lock3: Row-X (RX): used for Row Modification4: Share lock (S): blocks other DML operations5: S/Row-X dedicated shared rows (SRX): block other transaction

SQL statement for querying and deleting duplicate records1. Search for redundant duplicate records in the Table. duplicate records are determined based on a single field (Id ).Select * from table where Id in (select Id from Table group by Id having

/* Step 2: create a temporary tablespace */Create temporary tablespace user_tempTempfile 'd: \ oracle \ oradata \ Oracle9i \ user_temp.dbf'Size 50 mAutoextend onNext 50 m maxsize 20480 mExtent management local; /* Step 2: create a data table space *

Session: a Session is called in a computer, especially in a network application ".Session: In computer terminology, Session refers to the time interval between an end user and the Interaction System. It usually refers to the time between the user's

1. UPDATE nowait: query a piece of data and enable database transactions for it. If no lock is applied to the current data, the system returns the correct result and locks the current data. If the queried data is already in the transaction, the

Fault description: the problem of insufficient temporary tablespace has already been reported three times, and the customer is also bored. The first two were colleagues who added 5G data files. Currently, they have reached 40 GB, the occupied

At this time, if duplicate data exists in the temporary table, whether the primary key field businessid is repeated or the whole row is duplicated, an error in violation of the unique primary key constraint will be reported. Method: group by XX

Oracle 10g installation in win7, select advanced options, prompt program abnormal termination, an unknown error occursModify Oracle 10G \ database \ stage \ prereq \ db \ refhost. xmlIn the Go to the install directory and find the oraparam. ini file.

I. Query1. query the usage of oracle tablespaceSelect B. file_id File ID,B. tablespace_name tablespace,B. file_name physical file name,B. Total bytes,(B. bytes-sum (nvl (a. bytes, 0) already in use,Sum (nvl (a. bytes, 0) remaining,Sum (nvl (a. bytes,

Raise a code segment and ask for help.The code snippet is as follows:Copy codeThe Code is as follows:DeclareType t_indexby is table of numberIndex by binary_integer;Type t_nesteed is table of number;Type t_varray is varray (10) of number;V_indexby t_