Contents
How do you modify a database structure?
Changing the database structure with SQL queries. You can change the database structure with an ALTER query. The basic format for this query is ALTER TABLE tablename, followed by the specified changes. Table 3-7 shows the changes that you can make.
How do I update my live database?
Create a duplicate table – exact copy. Create a new table that does nothing more than keep track of the “up to date” table. MostCurrent (table) id (column) – holds name of table holding the “up to date” data. When repopulating, populate the older table and update MostCurrent.id to reflect this table.
What’s the best way to write a change in Liquibase?
Write changesets in a way that they can be rolled back. For example, use a relevant change clause instead of using a custom tag. Include a clause whenever a change doesn’t support an out-of-box rollback. (e.g., , , etc). Learn more about rollbacks. Leverage Liquibase to manage your reference data.
How to track changes in SQL Server database?
As a part of a Big Data project, we are often asked to find the best way to track the changes applied to the database tables, so that, no requirement is created to load all the huge tables to the data warehouse database at the end of the day, if not all of the data was changed.
Where do I store my changelogs in Liquibase?
Choose a package in your classpath to store the changelogs, preferably near your database access classes. In this example, we will use com/example/db/changelog. The master.xml includes the changelog for the releases in the correct order. In the example above it could look like this:
Which is the best way to perform alter table operations?
In coming lines we will go through performing ALTER table operations through T-SQL and also we will go through those tasks that are not directly supported through T-SQL. These involve table drop and recreation even when using T-SQL, so it is more convenient to carry out these using the SSMS table designer.