Flyway Migration Skill

Expert knowledge of Flyway database migrations for melosys-api's Oracle database.

Quick Reference

Migration Location

app/src/main/resources/db/migration/melosysDB/

Versioning Convention

Pattern	Example	Use Case
V{N}__	V150__name.sql	Major feature (current scheme)
V{N}.{M}__	V4.4_01__name.sql	Grouped related changes (legacy)
V{N}.{M}_{NN}__	V5.1_12__name.sql	Sub-feature in group (legacy)

Rules:

• Use double underscore __ after version
• Use descriptive snake_case names
• Never modify existing migrations
• Find latest version: ls -la app/src/main/resources/db/migration/melosysDB/ | tail -5

Current Version Range

Versions span from V1.0_01 (legacy dotted scheme) up through the current flat V15x series. Newer migrations use plain integer versions (V150__, V151__, ...). Always check the existing files for the true latest version before creating a new one — do not assume a fixed top number, it drifts:

ls app/src/main/resources/db/migration/melosysDB/ | sort -V | tail -5

Common Patterns

Create Table

CREATE TABLE my_table (
    id              NUMBER(19) GENERATED ALWAYS AS IDENTITY,
    fagsak_id       VARCHAR2(99) NOT NULL,
    status          VARCHAR2(50) NOT NULL,
    registrert_dato TIMESTAMP NOT NULL,
    endret_dato     TIMESTAMP NOT NULL,
    CONSTRAINT pk_my_table PRIMARY KEY (id),
    CONSTRAINT fk_my_table_fagsak FOREIGN KEY (fagsak_id) REFERENCES fagsak
);

CREATE INDEX idx_my_table_fagsak ON my_table(fagsak_id);

Create Lookup Table (Kodeverk)

CREATE TABLE my_type (
    kode VARCHAR2(50) NOT NULL,
    navn VARCHAR2(100) NOT NULL,
    CONSTRAINT pk_my_type PRIMARY KEY (kode)
);

INSERT INTO my_type(kode, navn) VALUES ('VALUE1', 'Description 1');
INSERT INTO my_type(kode, navn) VALUES ('VALUE2', 'Description 2');

Add Column

ALTER TABLE behandling ADD (
    my_column VARCHAR2(100) NULL
);

Add Column with Default

ALTER TABLE behandling ADD (
    my_flag NUMBER(1) DEFAULT 0 NOT NULL
);

Add Foreign Key

ALTER TABLE my_table ADD CONSTRAINT fk_my_table_ref
    FOREIGN KEY (ref_id) REFERENCES other_table;

Add Index

CREATE INDEX idx_my_table_column ON my_table(column_name);
CREATE UNIQUE INDEX idx_my_table_unique ON my_table(column1, column2);

Insert Process Type/Step

INSERT INTO PROSESS_TYPE(KODE, NAVN)
VALUES ('MY_PROCESS', 'Description of process');

INSERT INTO PROSESS_STEG(kode, navn)
VALUES ('MY_STEP', 'Description of step');

JSON Column (CLOB with constraint)

CREATE TABLE my_json_table (
    id   NUMBER(19) GENERATED ALWAYS AS IDENTITY,
    data CLOB NOT NULL,
    CONSTRAINT pk_my_json PRIMARY KEY (id),
    CONSTRAINT json_my_data CHECK (data IS JSON) ENABLE
);

Oracle-Specific Syntax

Data Types

Type	Usage
NUMBER(19)	IDs, large integers
NUMBER(1)	Boolean flags
VARCHAR2(N)	Variable text
CLOB	Large text/JSON
TIMESTAMP	Date/time
DATE	Date only

Identity Columns

-- Auto-increment ID
id NUMBER(19) GENERATED ALWAYS AS IDENTITY

Sequences

CREATE SEQUENCE my_seq
MINVALUE 1
NOMAXVALUE
INCREMENT BY 1;

Configuration

Maven Plugin (app/pom.xml)

<plugin>
    <groupId>org.flywaydb</groupId>
    <artifactId>flyway-maven-plugin</artifactId>
    <version>${flyway.version}</version>
</plugin>

Profile Settings

Profile	Flyway Enabled
local-mock	Yes (default)
local-q1	No
local-q2	No
nais	Yes

Commands

Check Migration Status

# Via Makefile
make db-info

# Via Maven
mvn flyway:info -pl app

Run Migrations

# Via Makefile
make db-migrate

# Via Maven
mvn flyway:migrate -pl app

Application Startup

Flyway runs automatically on application startup (unless disabled).

Debugging Migration Failures

For migration failures — checksum mismatch, ORA-00955 (object already exists), ORA-02292 (child record found), ORA-01430 (column already exists), partially applied migrations, flyway:repair/baseline, and local rollback — see references/debugging.md. It also covers flyway_schema_history inspection queries and safe column add/remove/rename patterns.

Best Practices

1. One logical change per migration
2. Test locally first with USE_LOCAL_DB=true
3. Never modify existing migrations in production
4. Use descriptive names that explain the change
5. Include indexes for foreign keys and query columns
6. Use NOT NULL where possible for data integrity
7. Add constraints with meaningful names (pk_, fk_, idx_, chk_)

Related Skills

• database: Schema structure and tables
• kodeverk: Lookup tables and enums
• behandling: Treatment tables
• fagsak: Case tables