database-schema

Is there any way to copy database structure without data in MySQL, so the new database will be the same as it is copied from, but with empty tables. After getting some suggestions I tried the command, but I am getting syntax error, my username = root and password = nothing . I guess the default one. I am trying following command, mysqldump -u root -p -d xyz_db | mysql -u root -p -Dnew_db what I am missing or misplacing in command? Raab mysqldump -u user -ppass -d olddb | mysql -u user -ppass -D newdb The new database must already exist. The -d flag in the mysqldump command prevents copying of

To prevent the usage of the schema attribute in the table annotation to all of my entities, I set the default schema name by the schema.xml: <?xml version="1.0" encoding="UTF-8"?> <entity-mappings xmlns="http://java.sun.com/xml/ns/persistence/orm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_2_0.xsd" version="2.0"> <persistence-unit-metadata> <persistence-unit-defaults> <schema>X</schema> </persistence-unit-defaults> </persistence-unit-metadata> </entity-mappings> And I set it as a mapping file in the persistence.xml:

I have an existing database which structure is used accross the whole application. Instances of the databases are periodically rotated. I have a database file template.sqlite which is used as a template for all newly created databases. I want to use it, not a creation script, so that I have to maintain only one file, the empty database template itself. I would like to create an in-memory database with the same structure based on that template file. I know I can open the database and read it's structure, then create the database manually in memory. If possible, I would like to be able to do it

How can I check when was the last time (timestamp) that I wrote in the database, irrespectively of the database table that I inserted into? Turned out to not be the answer (can't delete as accepted). See comments below this answer. I wasn't able to use information_schema.tables update_time as the column wasn't being updated but for create_time this worked. It would work for update_time (if changed) if update_time gets updated which might be true in your setup. select table_schema,table_name,max_time from information_schema.tables t1 JOIN (select MAX(t2.create_time) AS max_time FROM information

I have a small question concerning with how I should design my database. I have a table dogs for an animal shelter and I have a table owners. In the table dogs all dogs that are and once were in the shelter are being put. Now I want to make a relation between the table dogs and the table owners. The problem is, in this example not all dogs have an owner, and since an owner can have more than one dog, a possible foreign key should be put in the table dogs (a dog can't have more than one owner, at least not in the administration of the shelter). But if I do that, some dogs (the ones in the

I'm designing the database schema for a video production project management app and struggling with how to persist some embedded, but not repeatable data. In the few CS courses I took, part of normalizing a relational database was identifying repeatable blocks and encapsulating them into their own table. What if I have a block of embedded/nested data that I know is likely to be unique to the record? Example: A video record has many shoot_locations . Those locations are most likely never to be repeated. shoot_locations can also contain multiple shoot_times . Representing this in JSON, might