I am using Netbeans 7.4 to build my application. And also, I am using embedded java db. Now, I want to generate my JPA entities from my database from my database.
But, when I
rightclick my package -> New -> Entity classes from database, select my database, Available Tables is not showing up even a single one of the tables inside ANK schema.
One more strange thing I noticed is when I connect my db from Netbeans services tab, two schema options appear. First, APP in bold, second Other schemas. Schema APP don't have any tables. The tables are in ANK schema in Other schemas.
Can anybody tell me where I could have gone wrong?
I don't even know if I should be using java db, or I should go for pretty appealing h2, HSQL or some matured db like mysql.
The Nebeans interface to Derby is a bit tricky.
When creating a new database, only the APP schema is created by default (except for the SYS* schemas).
When you connect to the database without specifying a username, your default schema becomes APP
When connecting as user john, your default schema becomes john, BUT the schema john is NOT created, until you create an SQL object in it.
This means that if you create an initial connection to Derby in Netbeans as user john, you cannot choose john as the schema for the connection in the pull-down menu, because it has not been created yet. If you then choose another schema, create your table, disconnect and then create another connection you will be able to choose john as your schema, and you will find the table you created with the previous connection.
Even though you chose a different schema in the pull-down menu for the first connection, a schema with the same name as the username you connect as is created and set as default before starting to execute the create table statement.
Related
I'm using SQL Developer to host some data, but I think my configuration isn't right. Lets say I have a database named DB1 with the tables
DB1
-db1_name
-db1_cities
The problem is when I try to create a new database let say DB2, SQLdeveloper creates the database but it also includes all the tables from DB1 (db1_name,db1_cities). Also if I removed the tables from DB2, the tables also disappear from DB1. How can I change my configuration so this does not happen anymore and each database is independent from each other?
To create a new data base I usually go in the SQL Developer GUI interface to connections, then I click on new Connection and provide the connection name, user name, and password. I leave the connection type to basic and the role to default. The host name as local host, and the default port.
That's happening because you are currently adding a new database connection instead of creating a database.
To create a new database from scratch, take a look at this link, it'll take you through step by step on creating the new database.
I was creating MySQL database to add medicine.I created a table and I need to add one more tabe.After creating it I tried to query the database from the sql workbench.But it donot show the table but it is present in the EER Model.How can I solve this problem.
Modeling is just the task of abstractly designing your schema and its objects (e.g. tables, views etc.). It does not actually create these objects. For this you have to forward engineer your model to a server (see Database menu). Once done you can use the Synchronization feature to update either model or server (or both) with any changes made.
But keep in mind this is only for the objects, not for any data.
I have a database on SQL Azure which has an identity primary.
After using SQL Server Import and Export Wizard, I transferred the data to my SQL Server 2008 R2 database.
My ASP.NET Application runs fine and reads the data. But When I try to insert a value in a table 'User', it gives me an error:
Cannot insert null in column 'UserId'.
The reason being that it is not able to generate the identity value.
How can I overcome this issue?
PS: I tried Generating the scripts from SQL Azure, but the SQL file is 500MB in size and my host does not allow that big a script to run.
Edit: using Entity Framework for data access. The UserId field has an IDENTITY property (1,1).
Edit Tried to create the schema from SQLAzure Migration tool and then used the import/export data to copy the data.
But the wizard does not maintain the relations amongst the rows.
The data import/export wizard doesn't preserve the whole structure of your database objects.
i.e. it will only copy the data, not the whole structure of the table that the data fits into - including identity and key definitions.
You could import the data, and then manually set all the primary keys and default fields to match your desired database definition, or you could connect to your Azure instance and use the generate script option to generate your schema in the 2008 database prior to copying.
But the real answer is that you should be using the Copy Database Wizard to accomplish this, which works fine with Azure. It was designed for this scenario.
The issue was the wizard was trying to insert primary key values, which is disabled by default. And without inserting the primary keys, the relationships can't be maintained, thus the whole issue.
To resolve this issue and do a foolproof migration, ensure that the new schema maintains all the identity columns.
When selecting the source and destination tables, for the specific tables, click on "Edit Mappings" and Check the "Enable identity insert" check box to enable insertion of primary key values, which keep the structure and relations intact.
I moved some tables in my postgresql (8.2) database to a new schema.
at first, my "user" could not see the tables in the new schema, but I used set search_path to tell it to look in this new schema
I access these tables with a simple web application that uses hibernate. At first, my web application, which uses the "user" user, could not see the tables either, even after I set the search_path. I eventually set the default-schema in the hibernate config file and it worked, but I understand from what I've read that I should not have to set this property? I have a few JDBC queries in this app that still can't see the tables in the new schema.
I've browsed through the postgresql docs and can't find the cause of my problems. Is there something simple I'm missing?
SET search_path is not persisted. It is only valid for the current session.
You need to use ALTER USER to make that change permanently, but you don't need special privileges to change the user you are logged in with (i.e. "yourself")
Originally, I used Data Modelling in MySQL Workbench to design a database consisting of a series of tables (i.e. the columns and relationships).
Then using Database -> Forward Engineer, I created a database, and inserted data into the tables.
Now I've realised that the model I've designed needs some changes, and so I've altered some tables by inserted columns. My question is, how do I get MySQL Workbench to alter the tables?
Using Database -> Synchronize Model, Update Source just generates a bunch of CREATE TABLE IF NOT EXISTS sql statements, and as the tables exist, nothing changes.
What you are looking for is in the model menu Database / Synchronize model.
As I couldn't get get File -> Export -> Forward Engineer SQL ALTER Script to work, so I made a backup of the data, dropped the tables, recreated them, and then imported the data. I'd rather find a way to get MySQL Workbench to generate ALTER commands from the changes in my model
The 2011 answer is no longer up to date. I struggled to find the option in a recent version. Here is the new procedure (works for MySQLWorkbench 6.2 at least):
When you have finished editing your model, open Database -> Synchronize with Any Source
In the step Select Source you have 3 parts
Source : choose Model Schemadata
Destination : choose Live Database Server
Send updates to : choose whether the live database should be updated or if you only want to saves the changes to a .sql file
Proceed in the wizard, you can then review the tables and sql queries that will be executed. You can also ignore the update of some tables.