How do I view the ORACLE alert log? 1th/2 page _oracle

1. Understanding Oracle External Tables
External table Definition: The structure is stored in the data dictionary, and the table data is placed in the OS file in the table
Role: Querying the database for OS file data and loading OS file data into the database
Differences from other tables: DML operations cannot be performed on external tables and indexes on external tables can only be performed with the Select exercise
2. Build a simple external table 1. Build a file on the OS
Because the external table is primarily to view files on the OS, first build a file on the OS
Mkdir-p/oracle/ext
Vi/oracle/ext/ext.dat
10,20,30
40,50,60
70,80,90

2. Grant user permissions and create directory objects

Here we first build a new user

Create user test identified by ' 123 ' default tablespace test quota unlimited on test;

User authorization

Sql> Grant Create any directory to test;

Create a directory Object

Sql> Conn test/123 Connected. Sql> Create directory ext as '/oracle/ext '; Directory created.

3. Create an external table
sql> Create table exttable (
ID number,name varchar2 (a), I number
) Organization External
(Type Oracle_loader
Default directory Ext
　　Access Parameters
(Records delimited by newline
Fields terminated by ', '
) Location (' Ext.dat ')
);

4. Test

Sql> select * from Exttable; ID NAME I ---------- ---------- ---------- 10 20 30 40 50 60 90

Test is successful, visible in the database can query the OS file data

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