This is possibly more a database configuration problem than pgAdmin 4.
I work with two databases dev and test.
When I visualise common objects, one pgAdmin connection displays the table etc objects with a schema prefix the other does not. For example comparing two lines from a SELECT ... FROM statement (cf Schema Diff)
FROM df.pipe <-> FROM pipe
Can anyone point me in the direction of how to fix this ie both always show the schema prefix.
Related
I am experimenting with Data Flows in Azure Data Factory.
I have:
Set up a LinkedService to a SQL Server db. This db only has 2 tables.
The two tables are called "dummy_data_table1" and "dummy_data_table1" and are registered as Datasets
The ADF is copying data from these 2 tables, and in the Data Flow they are called "source1" and "source2"
However, when I select a source, go to Source options, and change Input from Table to Query and enter a simple query, it returns 0 columns (there are 11 columns in dummy_data_table1). I suspect my syntax is wrong, but how should I change it?
Hopefully this screenshot will help.
The problem was not the syntax. The problem was that the data flow could not recognize "dummy_data_table1" because it didn't refer to anything known. To make it work, I had to:
Enable Data Flow Debug (at the top of the page, not visible in my screenshot)
Once that's enabled, I had to click on "import projection" to import the schema of my table
Once this is done, the table name and fields are all automatically recognized and can be referenced to in the query just like one would do in SQL Server.
Source:
https://learn.microsoft.com/en-us/azure/data-factory/data-flow-source#import-schema
I have a database1 which has more than 500 tables and I have database2 which also has the same number of tables and in both the databases the name of tables are same.. some of the tables have different table definitions, for example a table reports in database1 has 9 columns and the table reports in database2 has 10.
I want to copy all the data from database1 to database2 and it should overwrite the same data and append the columns if structure does not match. I have tried the import export wizard in SQL Server 2008 but it gives an error when it comes to the last step of copying rows. I don't have the screen shot of that error right now, it is my office PC. It says that error inserting into the readonly column xyz, some times it says that vs_isbroken, for the read only column error as I mentioned a enabled the identity insert but it did not help..
Please help me. It is an opportunity in my office for me.
SSIS and SQL Server 2008 Wizards can be finicky tools.
If you get a "can't insert into column ABC", then it could be one of the following:
Inserting into a PK column -> when setting up the mappings, you need to indicate to overwrite the value
Inserting into a column with a smaller range -> for example from nvarchar(256) into nvarchar(50)
Inserting into a calculated column (pointed out by #Nick.McDermaid)
You could also get issues with referential integrity if your database uses this (most do).
If you're going to do this more often, then I suggest you build an SSIS package instead of using the wizard tooling. This way you will see warnings on all sorts of issues like the ones I've described above. You can then run your package on demand.
Another suggestion I would make, is that you insert DB1 into "stage" tables in DB2. These tables should have no relational integrity and will allow you to break the process into several steps as follows.
Stage the data from DB1 into DB2
Produce reports/queries on issues pertinent to your database/rules
Merge the data from stage tables into target tables using SQL
That last step is where you can use merge statements, or simple insert/updates depending on a key match. Using SQL here in the local database is then able to use set theory to manage the overlap of the two sets and figure out what is new or to be updated.
SSIS "can" do this, but you will not be able to do a bulk update using SSIS, whereas with SQL you can. SSIS would do what is known as RBAR (row by agonizing row), something slow and to be avoided.
I suggest you inform your seniors that this will take a little longer to ensure it is reliable and the results reportable. Then work step by step, reporting on each stages completion.
Another two small suggestions:
Create _Archive tables of each of the stage tables and add a Tstamp column to each. Merge into these after the stage step which will allow you to quickly see when which rows were introduced into DB2
After stage and before the SQL merge step, create indexes on your stage tables. This will improve the merge performance
Drop those Indexes after each merge, this will increase the bulk insert Performance
Basic on Staging (response to question clarification):
Links:
http://www.codeproject.com/Articles/173918/How-to-Create-your-First-SQL-Server-Integration-Se
http://www.jasonstrate.com/tag/31daysssis/
http://blogs.msdn.com/b/andreasderuiter/archive/2012/12/05/designing-an-etl-process-with-ssis-two-approaches-to-extracting-and-transforming-data.aspx
Staging is the act of moving data from one place to another without any checks.
First you need to create the target tables, the schema should match the source tables.
Open up BIDS and create a new Project and in it a new SSIS package.
In the package, create a connection for the source server and another for the destination.
Then create a data flow step, in the step create a data source for each table you want to copy from.
Connect each source to a new data destination and set the appropriate connection and table.
When done, save and do a test run.
Before the data flow step, you might like to add a SQL step that will truncate all the target tables.
If you're open to using tools then what about using something like Red Gate Sql Compare and Red Gate SQL Data Compare?
First I would use data compare to manage the schema differences, add the new columns you want to your destination database (database2) from the source (database1). Then with data compare you match the contents of the tables any columns it can't match based on names you specify how to handle. Then you can pick and choose what data you want to copy from your destination. So you'll see what data is new and what's different (you can delete data in the destination that's not in the source or ignore it). You can either have the tool do the work or create you a script to run when you want.
There's a 15 day trial if you want to experiment.
Seems like maybe you are looking for Replication technology as is offered by SQL Server Replication.
Well, if i understood your requirement correctly, you need to make database2 a replica of database1. Why not take a full backup of database1 and restore it as database2? Your database2 will be exactly what database1 is at the time of backup.
I have a dataset that pulls from multiple databases on the same server. Historically (without doing research) in this case I would set the data source to ReportServer (the database that houses the execution log for the server, ect.) and noticed the dataset doesn't seem to care what the data source is.
I did a few hours of digging and couldn't find an answer. When using (or in my case, unioning) multiple data bases in a dataset, what should the dataset data source be in Visual Studio?
Specifying the database in the connection string sets the starting, default database for the query. If your permissions are adequate, then there is nothing to stop you from accessing other databases.
The database in the connection string will give your query the context that is used when you don't specify a database name as part of a table. If your query is simply:
SELECT * FROM vw_Interactions
then this will run against the database specified in your connection string.
For your case, when using a table with the same name across multiple databases, the default database doesn't matter much, as long as the data access account has permissions that let the query work.
We're developing a Doctrine backed website using YAML to define our schema. Our schema changes regularly (including fk relations) so we need to do a lot of:
Doctrine::generateModelsFromYaml(APPPATH . 'models/yaml', APPPATH . 'models', array('generateTableClasses' => true));
Doctrine::dropDatabases();
Doctrine::createDatabases();
Doctrine::createTablesFromModels();
We would like to keep existing data and store it back in the re-created database. So I copy the data into a temporary database before the main db is dropped.
How do I get the data from the "old-scheme DB copy" to the "new-scheme DB"? (the new scheme only contains NEW columns, NO COLUMNS ARE REMOVED)
NOTE:
This obviously doesn't work because the column count doesn't match.
SELECT * FROM copy.Table INTO newscheme.Table
This obviously does work, however this is consuming too much time to write for every table:
SELECT old.col, old.col2, old.col3,'somenewdefaultvalue' FROM copy.Table as old INTO newscheme.Table
Have you looked into Migrations? They allow you to alter your database schema in programmatical way. WIthout losing data (unless you remove colums, of course)
How about writing a script (using the Doctrine classes for example) which parses the yaml schema files (both the previous version and the "next" version) and generates the sql scripts to run? It would be a one-time job and not require that much work. The benefit of generating manual migration scripts is that you can easily store them in the version control system and replay version steps later on. If that's not something you need, you can just gather up changes in the code and do it directly through the database driver.
Of course, the more fancy your schema changes becomes, the harder the maintenance will get i.e. column name changes, null to not null etc.
I've been writing a Library management Java app lately, and, up until now, the main Library database is stored in a .txt file which was later converted to ArrayList in Java for creating and editing the database and saving the alterations back to the .txt file again. A very primitive method indeed. Hence, having heard on SQL later on, I'm considering to port my preexisting .txt database to mySQL. Since I've absolutely no idea how SQL and specifically mySQL works, except for the fact that it can interact with Java code. Can you suggest me any books/websites to visit/buy? Will the book Head First with SQL ever help? especially when using Java code to interact with the SQL database? It should be mentioned that I'm already comfortable with using 3rd Party APIs.
View from 30,000 feet:
First, you'll need to figure out how to represent the text file data using the appropriate SQL tables and fields. Here is a good overview of the different SQL data types. If your data represents a single Library record, then you'll only need to create 1 table. This is definitely the simplest way to do it, as conversion will be able to work line-by-line. If the records contain a LOT of data duplication, the most appropriate approach is to create multiple tables so that your database doesn't duplicate data. You would then link these tables together using IDs.
When you've decided how to split up the data, you create a MySQL database, and within that database, you create the tables (a database is just something that holds multiple tables). Connecting to your MySQL server with the console and creating a database and tables is described in this MySQL tutorial.
Once you've got the database created, you'll need to write the code to access the database. The link from OMG Ponies shows how to use JDBC in the simplest way to connect to your database. You then use that connection to create Statement object, execute a query to insert, update, select or delete data. If you're selecting data, you get a ResultSet back and can view the data. Here's a tutorial for using JDBC to select and use data from a ResultSet.
Your first code should probably be a Java utility that reads the text file and inserts all the data into the database. Once you have the data in place, you'll be able to update the main program to read from the database instead of the file.
Know that the connection between a program and a SQL database is through a 'connection program'. You write an instruction in an SQL statement, say
Select * from Customer order by name;
and then set up to retrieve data one record at a time. Or in the other direction, you write
Insert into Customer (name, addr, ...) values (x, y, ...);
and either replace x, y, ... with actual values or bind them to the connection according to the interface.
With this understanding you should be able to read pretty much any book or JDBC API description and get started.