Usually, transactions occur on one database server: BEGIN TRANSACTION SELECT something FROM myTable UPDATE something IN myTable COMMIT A distributed transaction involves multiple servers: BEGIN TRANSACTION UPDATE amount = amount – 100 IN bankAccounts WHERE accountNr = 1 UPDATE amount = amount + 100 IN someRemoteDatabaseAtSomeOtherBank.bankAccounts WHERE accountNr = 2 COMMIT The difficulty comes from … Read more
SOURCE Database sqlpackage.exe /a:Extract /scs:Server=%Server%;Database=AspBaselineDB; /tf:%DriveSpec%\%DacPath%\%AspBaselineDB%_baseline.dacpac TARGET Database sqlpackage.exe /a:Extract /scs:Server=%Server%;Database=%AspTargetDB-2%; /tf:%DriveSpec%\%DacPath%\%AspTargetDB%.dacpac COMPARE & GENERATE the Delta script sqlpackage.exe /a:Script /sf:%DriveSpec%\%DacPath%\%AspBaselineDB%_baseline.dacpac /tf:%DriveSpec%\%DacPath%\AspNetDb\%AspTargetDB%.dacpac /tdn:aspTargetdb /op:%DriveSpec%\%SqlPath%\AspNetDb\AspDbUpdate.sql EXECUTE the script sqlcmd.exe -S %Server%\aspnetdbAmexDev -i %DriveSpec%\%SqlPath%\AspNetDb\AspDbUpdate.sql I do this in CMD scripting as our IT dept will not allow unsigned PowerShell scripts and they won’t purchase a cert. This … Read more
You should never modify a <changeSet> that was already executed. Liquibase calculates checksums for all executed changeSets and stores them in the log. It will then recalculate that checksum, compare it to the stored ones and fail the next time you run it if the checksums differ. What you need to do instead is to … Read more
I believe the problem is the use of UNION instead of UNION ALL. The UNION operator will combine the two sets and eliminate duplicates. Since CLOB types cannot be compared, the duplicate elimination part is not possible. Using UNION ALL won’t attempt to do duplicate elimination (you probably don’t have duplicates anyways) so it should … Read more
I built my own event sourcing lib and I opted for option 2 and here’s why. You query the event stream by aggregate id not event type. Reproducing the events in order would be a pain if they are all in different tables It would make upgrading events a bit of pain There is an … Read more
1) Concurrency. Do you have multiple people accessing the same dataset? Then it’s going to get pretty involved to broker all of the different readers and writers in a scalable fashion if you roll your own system. 2) Formatting and relationships: Is your data something that doesn’t fit neatly into a table structure? Long nucleotide … Read more
From the logical standpoint, a 1:1 relationship should always be merged into a single table. On the other hand, there may be physical considerations for such “vertical partitioning” or “row splitting”, especially if you know you’ll access some columns more frequently or in different pattern than the others, for example: You might want to cluster … Read more
Just add server_default or default argument to the column fields: created_on = db.Column(db.DateTime, server_default=db.func.now()) updated_on = db.Column(db.DateTime, server_default=db.func.now(), server_onupdate=db.func.now()) I prefer the {created,updated}_on column names. 😉 SQLAlchemy docs about column insert/update defaults. [Edit]: Updated code to use server_default arguments in the code. [Edit 2]: Replaced onupdate with server_onupdate arguments.
In the “database” section of the logon dialog box, enter //hostname.domain:port/database, in your case //123.45.67.89:1521/TEST – this assumes that you don’t want to set up a tnsnames.ora file/entry for some reason. Also make sure the firewall settings on your server are not blocking port 1521.
This should work just fine: # sudo mkdir /usr/local/var/postgres # sudo chmod 775 /usr/local/var/postgres # sudo chown construct /usr/local/var/postgres # initdb /usr/local/var/postgres use your username in place of construct. So, if your computer username is WDurant, the code will be: # sudo chown $(whoami) /usr/local/var/postgres