I have a MySql database and need some of the tables to have pre-created values. Its like a user needs to select a species of the pet he owns and I give him values from table "pet_species", like ["Fish","Dog","Cat",...,"Lizard"].
Also I have a table like "pet_breed" with pet_species_id, pet_breed_id, pet_breed_name. So is it possible to add the values in MySql Workbench or somewhere else, so it will look for all constraints while I add values, and then generate a right sql script to create or update this tables.
Hope you understand what I mean.
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I am looking to get all the update statements with old and new values within a database into one table.
For an example :
I have database name "users".
It contains four tables "primary_info","address_info","avtars","audit_logs"
Now, Whichever update statements executes on primary_info,address_info and avtars table that i need to log into audit logs table with below way.
ID, Table Name, Field_name,Old_value,New_value,Current Datetime
I know we can create triggers to manage such things.But i have database which contains more than 90 tables.So it won't help me to achieve by making trigger (update before) .
So is there any other way which i missed here ?
Thanks in advance.
I'm trying to work with YEAR function on one column in the DB and then add the results to a different table in the DWH.
What am I doing wrong?
INSERT INTO example_dwh1.dim_time (date_year)
SELECT YEAR(time_taken)
FROM exampledb.photos;
When removing the INSERT INTO line, I get the results I want, but I'm not able to insert them into the dwh table.
Thanks for your help!
The following select works, but I don't see the data in the table after the insert:
INSERT INTO example_dwh1.dim_time (date_year)
SELECT YEAR(time_taken)
FROM exampledb.photos;
There is rather broad. Assuming you have no errors in the insert, you might have:
You are incorrectly querying dim_time, so the data is there but your check is wrong.
You are inserting into dim_time in one database but querying it in another.
Assuming you have errors but are missing them, here are some possibilities:
The database does not exist.
The table does not exist.
The column is misnamed.
Other columns are declared NOT NULL.
Triggers defined on the table are preventing the insert.
Unique constraints/indexes on the table are preventing the insert.
Your question does not provide enough information to be more specific. However, it seems highly suspicious to be inserting a bunch of years -- which might include many duplicates -- into a dimension table.
I have two MySQL database k_db1 and k_db2 on a single server.
In k_db1, I have k_db1.table1 and k_db1.table2.
In k_db2, I have k_db2.table3 and k_db2.table4.
I want to create a third database k_db3 where I copy/paste tables of others databases.
It will result in k_db3.db1-table1, k_db3.db1-table2, k_db3.db2-table3, k_db3.db2-table4. I want to transfer data, indexes etc... and I don't want to delete k_db1 and k_db2 tables in the process. It must duplicate datas.
Do you know a way to do this just with SQL command?
Thanks in advance for your help.
You can try something like this:
DROP TABLE IF EXISTS k_db3.db1_table_1;
CREATE TABLE k_db3.db1_table_1 AS
SELECT * FROM db1.table_1;
Then you can recreate the indexes on the new table via ALTER TABLE statements.
Also I would avoid using - in table names.
Is it possible to use any sort of logic in MySQL without using any procedures? My web hosting does not let me create any procedures so I'm looking for a workaround.
The type of thing I want to do is only add an item to a table if it doesn't already exist. Or add a column to a table if it's not already there. There are some operations that can be done such as CREATE TABLE IF NOT EXISTS and so on, but some operations I require do not have such luxuries :(
I realised late on that my lovely procs won't work and so I tried writing IF/ELSE logic as top-level queries, but for MySQL, IF ELSE blocks only seem to work inside functions/procs and not at the global scope.
Any workarounds greatfully received - I've already asked the hosting to grant me privileges to create procedures but no reply as yet...
I suppose you don't have access to the INFORMATION_SCHEMA either. You can possibly find solutions but it would be better, in my oninion, to:
Change your hosting provider. Seriously. Pay more - if needed - for a MySQL instance that you can configure to your needs. You only have a crippled DBMS if you are not allowed to create procedures and functions.
Posible workarounds for the specific task: You want to add a column if it doesn't exist.
1) Just ALTER TABLE and add the column. If it already exists, you'll get an error. You can catch that error, in your application.
2) (If you have no access to the INFORMATION_SCHEMA) maintain a version of the schema, for your database.
The best solution that I can think of would be to use an additional language with SQL. For example, you can run a query for a specific record, and based on the response that you get, you can conditionally run an INSERT statement.
For inserting a table if it doesn't exist, try using the SHOW TABLES statement and testing whether or not a name exists in the result set.
MySQL supports INSERT IGNORE. and INSERT ... ON DUPLICATE KEY UPDATE.
The following will insert a new row, but only if there is no existing row with id=10. (This assumes that id is defined as a unique or primary key).
INSERT IGNORE INTO my_table (id, col1, col2) values (10, "abc", "def");
The following will insert a new row, but if there is an existing row with id=10 (again, assuming id is unique or primary), the existing row will be updated to hold the new values, instead of inserting a new row.
INSERT INTO my_table (id, col1, col2) values (10, "abc", "def")
ON DUPLICATE KEY UPDATE col1=VALUES(col1), col2=VALUES(col2)
Also, CREATE TABLE supports the IF NOT EXISTS modifier. So you can do something like:
CREATE TABLE IF NOT EXISTS my_table ...
There are many other similar options and modifiers available in MySQL. Check the docs for more.
Originally I created a big script to create or update the database schema, to make it easier to deploy database changes from my local machine to the server.
My script was doing a lot of "if table 'abc' exists and it doesn't have a FK constraint called 'blah'" then create an FK constraint called 'blah' on table 'abc'... and so on.
I now realise it's not actually necessary to check whether a table has a certain column or constraint etc, because I can just maintain a schema-versioning system, and query the DB schema-version when my app starts, or when I navigate to a certain page.
e.g. let's say I want to add a new column to a table. It works like this:
Add a new migration script to the app code, containing the SQL required to add the column to the existing table
Increment the app's schema-version by 1
On app startup, the app queries the DB for the DB's schema-version
If DB schema-version < app schema-version, execute the SQL migration scripts between the two schema-versions, and then update the DB schema-version to be the same as the app
e.g. if the DB's schema-version is 5 and the app version is 8, the app will apply migration scripts 5-6, 6-7 and 7-8 to the DB. These can just be run without having to check anything on the DB side.
The app is therefore solely responsible for updating the DB schema and there's no need for me to ever have to execute schema change scripts on the local or remote DB.
I think it's a better system than the one I was trying to implement for my question.
I'm trying come up with the best method of synchronizing particular rows of 2 different database tables. So, for example there's 2 product tables in different databases as such...
Origin Database
product{
merchant_id,
product_id,
... additional fields
}
Destination Database
product{
merchant_id
product_id
... additional fields
}
So, the database schema is the same for both. However I'm looking to select records with a particular merchant_id, remove all records from the destination table that have that merchant_id and replace those records with records from the origin database of the same merchant_id.
My first thought was using mysqldump, parsing out the create table statements, and only running the Insert Statements. Seems like a pain though. So I was wondering if there is a better technique to do this.
I would think mysql has some method of creating INSERT statements as output from a SELECT statement, so you can define how to insert specific record information into a new db.
Any help would be appreciated, thank you much.
phpMyAdmin has part of this capability: You can run a query and then export the results of that query into a file containing CREATE statements.
Update: And mysqldump has it too: Link
mysqldump -u username -p --where="id='merchant_id'" databasename
In regards to replacing merchant IDs, that part I don't entirely understand yet. You may be better off doing a manual search+replace on them. Can you make a real life example of two such records?