ORA-01658: Unable to create INITIAL extent for segment in tablespace

You are trying to create a new object, but the initial extent does not fit into the tablespace specified.

There is not enough space left inside the tablespace either due to the datafiles being full, autoextend which is not set at datafile level or due to a disk which's full.

You'll have to check the size of the datafiles attached to the tablespace and check whether they can autoextend or not..
Alternatively you can specify a smaller size for the initial extent.

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select file_name, bytes, autoextensible, maxbytes from dba_data_files where tablespace_name='TABLESPACE_NAME'

Either add more datafiles to the tablespace, set the autoextensible flag or enlarge the datafile(s).

To add more space to a file issue following command:

1.	alter database datafile 'C:\ORACLE\ORADATA\TOOLS01.DBF' resize 1000m;

To turn on the autoextend feature on a datafile use following command:

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alter database datafile 'C:\ORACLE\ORADATA\TOOLS01.DBF' autoextend on next 100m maxsize 2000m;

To add a new datafile to the tablespace use following command:

1. 2.

alter tablespace TOOLS add datafile 'C:\ORACLE\ORADATA\TOOLS02.DBF' autoextend on next 100m maxsize 2000m;