Mysql – How to read this output from MySQL

Simple answer do not mix with your other assumption. I hope you know primary key and foreign key relation for eg:

• Primary key in a table is nothing but a column that is unique + not null where as foreign key is referring to that primary key table column.

• If data inserting into foreign key table column that not matches to primary key it is nothing but duplicate record and it'll not insert with error throw.

• In DB2 Load it'll not check duplicate/dependencies between two tables (primary key and foreign key table) bypass records and load data.

DB2 recommends checking dependency/duplicate record in terms of set integrity check after Load, if no duplicate/dependency found it'll take out your table from check integrity and if found you can create another table to put duplicate records into that and bring out from check integrity.

Query to check tables in check integrity after Load:

db2 "select 'set integrity for '||tabschema||'.'||tabname||' immediate checked ;' 
from syscat.tables where tabschema='<schemaname for eg:HEDW' and not (status='N'
and access_mode='F')"

Command to bring out from check integrity:

db2 set integrity for HEDW    .EMPLY_BON_TIME immediate checked
DB20000I  The SQL command completed successfully.

It isn't saying that there is a duplicate entry in the table already, it is saying that there is already one entry in there with that value for the primary key and it is refusing to insert a second for that reason.

I suspect if you run:

SELECT * 
FROM   <table> 
WHERE  <keyfield> = 'Upping Your Type Game-http://jessicahische.is/talkingtype'

or if that key is a composite

SELECT * 
FROM   <table> 
WHERE  <keyfield1> = 'Upping Your Type Game' 
AND    <keyfield2> = 'http://jessicahische.is/talkingtype'

You will find one matching row, and that your code at the point of the error is trying to insert a second.

Dealing with duplicates on insert:

If you try INSERT a duplicate values for a primary key (or a unique index) you will always get that error. There are a couple of ways around it: check before you insert and either do an update (if something might have changed) or just don't do anything.

There is also the mysql specific ON DUPLICATE KEY UPDATE option (see https://stackoverflow.com/questions/1218905/how-do-i-update-if-exists-insert-if-not-aka-upsert-or-merge-in-mysql) if you are happy to sacrifice compatibility with other RDBMSs.

As of version 9.5 Postgres supports a similar feature with slightly different syntax (ON CONFLICT DO UPDATE/NOTHING - see https://wiki.postgresql.org/wiki/UPSERT).

MS SQL Server, Oracle and some other systems support MERGE statements as defined in the SQL:2003 standard (see https://en.wikipedia.org/wiki/Merge_(SQL)) which is intended to achieve the same functionality and more. Be careful with any of these options if cross database compatibility is (or is likely to be in future) one of your goals.