Database Link

What DB Link Can and Cannot Do

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Can and Cannot For better understanding the features of a database link which may play an important role in data migration, we should study what a database link can and cannot do in a distributed database system in order to develop our data migration strategy. Generally speaking, you can perform Data Query Language (DQL) and […]
SQL

4 Types of SQL in Relational Database

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Types of SQL Statements SQL statements in relational database management system (RDBMS) could sometimes be too complicated to be analyzed for. As SQL developers, we should at least be able to distinguish what types of the statements that are using. According to conventional SQL classification, there are 4 basic types of SQL statements. Data Query […]
DDL

How to Resolve ORA-02494: invalid or missing maximum file size in MAXSIZE clause

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Generated DDL from tools may not be executable sometimes. I got ORA-02494 when I execute DDL scripts that were generated from other database by TOAD, a very popular administration tool used by DBA. Irrational DDL SQL> CREATE TABLESPACE PERSON DATAFILE   2    ‘/u02/app/oracle/oradata/datastore/.ACFS/snaps/orcl/ORCL/datafile/user01.dbf’ SIZE 5G AUTOEXTEND ON NEXT 20M MAXSIZE 4G   3  LOGGING […]