Mass is not updating database
When we change a column’s data type (for example, from .
It is called a migration script because it changes all or part of a database from one version to another. This alteration can be as simple as adding or removing a column to a table, or a complex refactoring task such as splitting tables or changing column properties in a way that could affect the data it stores.
For every likely migration path between database versions, we need to store in version control the migration scripts that describe precisely those steps required to perform the change and, if necessary, moving data around and transforming it in the process Migration scripts are of two types: Migration scripts can be forward or “up” migrations that go to a newer version of a database, or backward, or “down” migrations to fall back to a previous version of a database.
Likewise, a column merge would create a new column and drop the original columns.
In either case, any data in the dropped column(s) will be lost.
It isn’t wise to change a script once it has been run successfully, and the same set of migration scripts should be run in every server environment where the deployment is taking place.
Unfortunately, there is no standard way of attaching a version to a SQL Server Database.
For example, if we know that a migration script is intended for version 1.5, we can have the script start by interrogating the current version number of the target database, and aborting if it isn’t “1.5”.To bring a database up-to-date, for example, all that is necessary is to run in the correct order the “up” migration scripts that will transform the target database from its current version to the latest version in source control.A ‘build script’ is then merely a special case of a migration script that migrates the database from nowhere to the first version.We can create a manual migration script to modify rows appropriately that would otherwise be truncated.Regardless of how we generate the migration script, we may not be able to run it “as is” on a large database, especially one that is in production use.Instead, we can create a manual migration script to create the new column(s), run custom SQL to move the data, and then drop the original column(s).