Here I need to insert huge records to my database tables. How can I do that in PostgreSQL 9.3 version?
Example:
/* Table creation */
create table tabletest(slno int,name text,lname text, address text, city text);
/* Records insertion */
insert into tabletest values -- Here i need to insert thousands of records in a bulk.
Short answer: use the COPY command.
Details available in the Postgres 9.3 documentation
Note that the file should be available to the Postgres server machine because COPY is meant to be used mainly by DBAs.
And, if you have Excel, you'd have to export the data to CSV format first as Postgres cannot read Excel-formatted data directly.
Related
We daily receive 7 millions of records , we are going to append to the existing target table.The target table is partitioned based on date
We are using DB2 Load command to load data from one DB2 table (stage) to another DB2 table target
call SYSPROC.ADMIN_CMD('LOAD FROM (SELECT * FROM stage_table )
OF CURSOR INSERT INTO target_table NONRECOVERABLE INDEXING MODE INCREMENTAL ALLOW READ ACCESS')
As per IBM documentation , ALLOW READ ACCESS is going to be deprecated suggested to use INGEST method instead of that
https://www.ibm.com/docs/en/db2/10.1.0?topic=functionality-fp1-allow-read-access-parameter-load-command
Question:
How to use INGEST method to load data from DB2 to DB2 tables ?
what would be other alternatives to load millions of records with improved performance.
In SQL stored procedures, we have an option of creating a temporary table "#temp" whose structure is as that of another table that it is referring to. Here we don't explicitly create and mention the structure of "#temp" table.
Do we have similar option is HQL Hive script to create a temp table during run time without actually creating the table structure. Thus I can dump data to temp table and use it. Below code shows an example of #temp table in SQL.
SELECT name, age, gender
INTO #MaleStudents
FROM student
WHERE gender = 'Male'
Hive has the concept of temporary tables, which are local to a user's session. These tables behave just like any other table, and can be created using CTAS commands too. Hive automatically deletes all temporary tables at the end of the Hive session in which they are created.
Read more about them here.
Hive Documentation
DWGEEK
You can create simple temporary table. On this table you can perform any operation.
Once you are done with work and log out of your session they will be deleted automatically.
Syntax for temporary table is :
CREATE TEMPORARY TABLE TABLE_NAME_HERE (key string, value string)
As Redshift is based on PostgreSQL, does it have an option to overwrite or append data in table while copying from S3 to redshift?
Only thing I got is use of triggers but they don't accept any argument.
All I need to write a script which takes an argument as yes/no (or similar) if the data is already in the table.
When loading data from Amazon S3 into Amazon Redshift using the COPY command, data is appended to the target table.
Redshift does not have an "overwrite" option. If you wish to replace existing data with the data being loaded, you could:
Load the data into a temporary table
Delete rows in the main table that match the incoming data, eg:
DELETE FROM main-table WHERE id IN (SELECT id from temp-table)
Copy the rows from the temporary table to the main table, eg:
SELECT * FROM temp-table INTO main-table
See: Updating and Inserting New Data
Redshift doesn't allow you to create triggers or events like other sql databases, the solution I found is to run update (sql query)though you can use also Python or other language and schedule the Rscript with crontab task.
As of May 2019, Redshift supports stored procedures so you can package up a set of queries/statements like this:
CREATE OR REPLACE PROCEDURE public.copy_and_cleanse_data(overwrite bool)
AS $$
BEGIN
if overwrite IS TRUE THEN DELETE FROM myredshifttable;
copy myredshifttable
from 's3://awssampledbuswest2/tickit/category_pipe.txt'
iam_role 'arn:aws:iam::<aws-account-id>:role/<role-name>'
region 'us-west-2';
UPDATE myredshifttable SET myfield = REPLACE(myfield, 'foo', 'bar');
END;
$$ LANGUAGE plpgsql
SECURITY DEFINER;
Then use or schedule the following query:
CALL public.copy_and_cleanse_data()
I am using PostgreSQL database for live project. In which, I have one table with 8 columns.
This table contains millions of rows, so to make search faster from table, I want to delete and store old entries from this table to new another table.
To do so, I know one approach:
first select some rows
create new table
store this rows in that table
than delete from main table.
But it takes too much time and it is not efficient.
So I want to know what is the best possible approach to perform this in postgresql database?
Postgresql version: 9.4.2.
Approx number of rows: 8000000
I want to move rows: 2000000
You can use CTE (common table expressions) to move rows in a single SQL statement (more in the documentation):
with delta as (
delete from one_table where ...
returning *
)
insert into another_table
select * from delta;
But think carefully whether you actually need it. Like a_horse_with_no_name said in the comment, tuning your queries might be enough.
This is a sample code for copying data between two table of same.
Here i used different DB, one is my production DB and other is my testing DB
INSERT INTO "Table2"
select * from dblink('dbname=DB1 dbname=DB2 user=postgres password=root',
'select "col1","Col2" from "Table1"')
as t1(a character varying,b character varying);
I want to dump a subset of a table of my postgres database. Is there a way to dump a SELECT statement without creating a view?
I need to copy a part of the table to an other postgres database.
Use COPY to dump it directly to disk.
Example (from the fine manual) using a SELECT:
COPY
(SELECT * FROM country WHERE country_name LIKE 'A%')
TO '/usr1/proj/bray/sql/a_list_countries.copy';