Oracle

I thought it was simple, and I found some pits.1. Installing Cx_oraclePip Install Cx_oracle2. Download InstantclientThen unzip the oci.dll copy to the $python_home or $Python _home\lib\site-packages directory, note must be consistent version,

(Reproduced: https://www.cnblogs.com/iceword/archive/2011/02/15/1955337.html)SELECT * FROM Awhere ID in (select ID from B)The above query uses the in statement, in () executes only once, it detects all the ID fields in table B and caches them. After

1.sid:Format one: Oracle JDBC Thin using an SID:Jdbc:oracle:thin: @host:p Ort:sidExample:jdbc:oracle:thin: @localhost: 1521:ORCLThis format is the simplest and most usedYour Oracle SID can be obtained through a command:Sqlplus/as SYSDBASelect value

--Retrieve data from one hours agoSELECT * from sys_system_dictionary as of timestamp sysdate-1/24ORDER BY ID The use of the as of timestamp method is very convenient, but in some cases we recommend using the as of SCN to execute flashback

--Delete PartitionALTER TABLE tt_trms_all_air_task DROP PARTITION tt_trms_all_air_task_p20171030;1. Add a partitionALTER TABLE Tt_trms_all_air_taskADD PARTITION tt_trms_all_air_task_p20171031 VALUES less THAN (TIMESTAMP ' 2017-10-31 00:00:00

Automated management of memory in Oracle 11gThe value of Memory_target is greater than/DEV/SHM and will error Ora-00845:memory_target not supported on the This system fault,In Redhat series systems, the default value of/DEV/SHM is half the total

1, query table space, and table space sizeSELECT T.tablespace_name, round (SUM (Bytes/(1024x768)), 0) ts_sizeFrom Dba_tablespaces T, Dba_data_files DWHERE T.tablespace_name = D.tablespace_nameGROUP by T.tablespace_name;2. File system address of

--Create a tableCreate TableBrowser_track (Btid Number not NULL, opend_idvarchar2( -) not NULL, Url_addressvarchar2( -) not NULL, paramsvarchar2( -)NULL, Stay_time Number default 0 not NULL, Look_time Number default 0 not NULL,

DECLARE CURSOR user_cur is select * from My_user;  User_row My_user%rowtype;      Begin open User_cur;      Loop fetch user_cur into User_row;      Exit when User_cur%notfound; Dbms_output.put_line (user_row.user_id| | ' ----'||      User_row.name); 

Numeric functions:1.round: Returns the value after roundingRound (number, parameter) parameter does not write default to 0The following parameter specifies the precision of the return value, or the start of rounding from the beginning of the decimal

--View the table under table spaceSelect T.table_name,t.tablespace_name from Dba_tables t where T.tablespace_name = ' ${spacename} ' and owner = ' ${owner} ';--View the index under Table spaceSelect T.index_name,t.tablespace_name from dba_indexes t

When we started to insert large amounts of data into an empty indexed table, there was no fragmentation problem, but after a long period of additions and deletions, the database will inevitably have fragmentation problems that affect the performance

Prepare two devices, take my example a source ip:192.168.3.66 and a duplicate ip:192.168.3.771 "Copy the database based on the backup set, the directory structure is the same (Active database network)1. Check the duplicate to see if there are any

Long: variable long string data, longest 2g,long with VARCHAR2 column, can store long text up to one long column in a tableLong RAW: variable Long binary data, up to 2GCLOB: Character large object CLOB used to store single-byte character dataNCLOB:

After each database upgrade, the objects in the library need to be recompiled. Here's a script that can be compiled in batches to compile these defunct objects in a single execution. It is important to note that because of the permissions problem,

Oracle integrity constraints are incorrect. oracle integrity constraints ErrorCaused by: org. hibernate. exception. ConstraintViolationException: cocould not execute JDBC batch updateORA-02291: violation of complete constraints (UNISPOWER.

Oracle transaction isolation level and read consistency, oracle consistency Oracle provides three isolation levels: 1. Read and submit. In short, only data submitted before the execution of the statement can be read. 2. serialization. This is a

Oracle synonym, oraclesynonym Synonym: For another data object, the synonym is an alias that depends on the target object. If the target object is changed or deleted, the synonym becomes invalid. Synonyms cannot replace the privileges of database

Oracle replication database, oracle Database Prepare two devices, for example, one source ip Address: 192.168.3.66 and one duplicate ip Address: 192.168.3.77. 1. Copy the database based on the backup set, and the directory structure is the same

Small table hotspot disks with abnormal methods for conversion of large data volumes, abnormal hot spots   I encountered a strange problem. There are two tables, which are about 0.3 billion of the Data. Table A has the A1 field, table B has the B1