I. Introduction of row migration and row link in actual work we often encounter some problems with low Oracle database performance. Of course, there are many reasons that cause low Oracle database performance, we can use some correct design and
The new Listagg function in the Oracle 11g Release 2 release, Listagg is an Oracle built-in function that implements string aggregation;Listagg (column, ' delimiter ') within group (Order by column)-(Partition by column)The delimiter can be
An example of the row-to-column and column-to-Row Operations in Oracle Data Tables.
Row-to-ColumnOne table
The query result is
-- Row-to-column Conversion
select years,(select amount from Tb_Amount as A where month=1 and A.years=Tb_Amount.years)as
Oracle row-to-column summary and oracle column-to-column Summary
Recently, I have applied row-to-column conversion in my work. Here I will make a simple summary.
The conversion process is as follows:
1. Create a table structure
CREATE TABLE
If you want to sort out the FAQs in Oracle, I think the row-to-column conversion problem is inevitable. Today, I used some leisure time to sort out my understanding and experiences. Before proceeding to my summary, I repeatedly thought about the
Multi-line Turn stringThis is relatively simple, with | | Or the CONCAT function can be implementedSelect Concat (id,username) str from App_userselect id| | Username Str from App_userString to multiple columnsis actually the problem of splitting the
In my previous articles, I have discussed the danger of adding default columns to a data table, especially in online production environments. A default column is added to a large data table, which has the following serious hazards: The system runs
HBase vs. Oracle comparison (column and row database)1 Main differences
HBase is suitable for a large number of insertions and read cases
The bottleneck of HBase is hard drive transfer speed , and Oracle's bottleneck is hard drive seek
Methods for column encryption in Oracle 2011-12-22 17:21:13Category: LinuxOracle supports multiple column encryption methods:1, transparent Data encryption (TDE):CREATE TABLE Encrypt_col (id int,TXT VARCHAR2 (+) encrypt using ' algorithm name '
Reference article: http://blog.csdn.net/tianlesoftware/article/details/4704858Multi-line turn string This is relatively simple, with | | Or the CONCAT function can be implementedSelect Concat (id,username) str from App_userselect id| | Username Str
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