Constraints when migrating from Oracle to Postgres?|EverExpanse

Constraints when migrating from Oracle to Postgres?

When Migrating Schema from Oracle to Postgres, there are few object differences to pay attention to in which one of the object is Constraint.

Here are some key constraint differences to take into account:

Primary Key Constraints:

The primary key constraint in Oracle and PostgreSQL serves the same fundamental purpose, it uniquely identifies each record in a table. However, there are differences in how primary key constraints are defined and managed in each database system like syntax, Composite primary keys, Auto-incrementing columns, Behavior on NULL values.

Foreign Key Constraints:

PostgreSQL supports foreign key constraints similarly to Oracle, but there are some syntax differences. Ensure that foreign key constraints are defined with the appropriate syntax in PostgreSQL, and verify that referential integrity is maintained after migration.

Check Constraints:

Check constraints are used to enforce domain integrity by limiting the values that can be inserted into a column. While both Oracle and PostgreSQL support check constraints, there may be differences in the allowed syntax and expressions.Review and adjust check constraints as needed during migration.

Unique Constraints:

Unique constraints ensure that the values in a column or a combination of columns are unique across rows in a table. While Oracle and PostgreSQL both support unique constraints, the syntax for defining them may differ slightly. Verify that unique constraints are defined correctly in PostgreSQL to ensure data integrity.

Default Value Constraints:

Default value constraints specify a default value for a column if no value is provided during insertion. Both Oracle and PostgreSQL support default value constraints, but there may be differences in the allowed data types and expressions. Adjust default value constraints as necessary during migration.

Enforcement of Constraints:

While both Oracle and PostgreSQL enforce constraints, there may be differences in how constraints are enforced, especially during data manipulation operations. Test data manipulation operations after migration to ensure that constraints are enforced correctly in PostgreSQL.

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