alter table remove default value oracle

ORACLE 11G when exported with export, empty tables cannot be exported. There is a new feature in 11G that does not allocate segment when there is no data in the table to save space Workaround: 1, insert a line, and then rollback will produce segment. The method is to insert data in an empty table and then delete it, resulting in segment. When you export, y

Oracle scott user Default table EMP (employee table) NO field type description 1 empno number (4) employee NUMBER 2 ENAME VARCHAR2 (10) employee name 3 JOB VARCHAR2 (9) job position 4 mgr number (4) represents an employee's lead NUMBER 5 hiredate date represents employment DATE 6 sal number () represents monthly salary

In oracle11g, when each table is initially created, the default is to not allocate extents to this object.When the data is first inserted, the corresponding extents are assigned.The corresponding control parameter is Deferred_segment_creation=trueIf you want to maintain a property that is consistent with the lower version, you can set this parameter value to Flas

Sometimes the development of the table structure design, is too random to table field is empty, such as ID1=ID2, if the Allowed field is empty, because the Oracle hollow value is not equal to null value, it is possible to get unexpected results. Beyond that, the key is that

Sometimes the development of table structure design, whether the table field is empty is too casual, such as id1 = id2, if the field is allowed to be empty, because the Oracle empty value is not equal to the null value, unexpected results may be obtained. In addition, NULL a

querying the table space in the current database whether to expand automatically Select tablespace_name,file_name,autoextensible from Dba_data_files;To automatically expand the table space by modifying the data file for the tablespace, and limit the maximum file sizeALTER DATABASE datafile '/OPT/APP/ORACLE/ORADATA/CAACDB/SYSTEM01.DBF ' autoextend on NEXT 50M max

Oracle exception [ORA-22908: NULL Table value reference] Problem Analysis and Solution Oracle exception [ORA-22908: NULL Table value reference] Problem Analysis and Solution The scenario is as follows:Type list_obj; test (nam

Tags: show color kanji specify query column queue ACL insertSql> Conn Scott/tigerConnected.Sql> Show user;USER is "SCOTT"Sql> CREATE TABLE QQ (name VARCHAR2 (ten), salary number (8,2));Create a table QQ, two segments, name and salaryTable created.Sql> SELECT * from QQ;Enquiry Form QQ InformationNo rows selectedSql> INSERT INTO QQ (name) VALUES (' Zhangsan ');Specify a queue to insert data, NULL not set1 row

Tags: PNG family pre ora multiple oracl condition color NATExcerpt: https://www.linuxidc.com/Linux/2012-06/62894.htmWhen the case condition then condition is true the value of the else condition is false when the value end--Single query unify the number of times a field equals a valueSelect COUNT (M.underwriteflag) from prpcmain m where m.underwriteflag= ' 1 ' ;--720407select count (M.nationflag) from Prpc

The business description is as follows: When inserting a table, you need to update the value of another field based on the value of one field. Of course, it can also be implemented through a program, but this field is only used for data exchange. It has nothing to do with the main business of the system and does not want to modify the program. Therefore, it can b

,'a0123456789',' ')) intoV_len fromdual; the whileV_indexV_len+1Loop - SELECTRegexp_substr (V_dict_text,'[[: alnum:]]+',1, V_index) intoV_temp1 fromdual; - SELECT TEXT intoV_temp2 fromA1WHEREId=V_temp1; -V_result:=Concat (Concat (V_RESULT,V_TEMP2),','); +V_index:=V_index+1; - EndLoop; + RETURNSUBSTR (V_result,0, Length (V_result)-1); A EndConverter; at - //test results, such as successful conversion of dictionary values to text values - SELECTBid,converter (BID)TEXT fromB1