cesnimda
40 lines
1.7 KiB
Markdown
40 lines
1.7 KiB
Markdown
# Migrations and compatibility
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The API applies EF Core migrations on startup and performs guarded legacy-schema reconciliation for SQLite and MariaDB/MySQL compatibility. Fresh and repeated disposable SQLite migration chains are the normal local verification; generated provider SQL is not proof of a live production migration.
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The `Job`/`JobApplication` opportunity cutover is an expand/verify/contract change. Keep dual writes and compatibility reads until a production report and restored-backup rehearsal pass, then observe one release before removing legacy columns in a later migration. Never edit the history of an applied migration.
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### Production cutover validation
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After the additive backfill, run these read-only MariaDB/MySQL checks against production and a restored
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backup. Every result must be `0`; do not turn them into an update script.
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```sql
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SELECT COUNT(*) AS missing_job
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FROM JobApplications
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WHERE JobId IS NULL;
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SELECT COUNT(*) AS missing_target
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FROM JobApplications a
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LEFT JOIN Jobs j ON j.Id = a.JobId
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WHERE a.JobId IS NOT NULL AND j.Id IS NULL;
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SELECT COUNT(*) AS owner_mismatch
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FROM JobApplications a
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JOIN Jobs j ON j.Id = a.JobId
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WHERE NOT (a.OwnerUserId <=> j.OwnerUserId);
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SELECT COUNT(*) AS field_mismatch
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FROM JobApplications a
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JOIN Jobs j ON j.Id = a.JobId
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WHERE NOT (a.CompanyId <=> j.CompanyId)
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OR NOT (a.JobTitle <=> j.JobTitle)
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OR NOT (a.Location <=> j.Location)
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OR NOT (a.JobUrl <=> j.JobUrl)
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OR NOT (a.Description <=> j.Description)
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OR NOT (a.Salary <=> j.Salary);
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```
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Observe one release after the checks pass, then change reads, re-run the checks on a fresh restore, and
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only then make `JobId` required and remove duplicated opportunity columns in a later migration.
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