diff --git a/README.md b/README.md
index 8bad291f..6485def5 100644
--- a/README.md
+++ b/README.md
@@ -32,3 +32,11 @@ Flamenco Manager has a SwaggerUI interface at http://localhost:8080/api/swagger-
 ## Database
 
 Flamenco Manager includes a copy of https://github.com/go-gorm/sqlite.git, adjusted to use the pure-Go SQLite from https://modernc.org/sqlite.
+
+Flamenco Manager and Worker use SQLite as database, and Gorm as
+object-relational mapper.
+
+Since SQLite has limited support for altering table schemas, migration requires
+copying old data to a temporary table with the new schema, then swap out the
+tables. Because of this, avoid `NOT NULL` columns, as they will be problematic
+in this process.
diff --git a/internal/manager/persistence/jobs.go b/internal/manager/persistence/jobs.go
index dac02859..aa143d21 100644
--- a/internal/manager/persistence/jobs.go
+++ b/internal/manager/persistence/jobs.go
@@ -35,12 +35,12 @@ import (
 
 type Job struct {
 	gorm.Model
-	UUID string `gorm:"type:char(36);not null;unique;index"`
+	UUID string `gorm:"type:char(36);default:'';unique;index"`
 
-	Name     string        `gorm:"type:varchar(64);not null"`
-	JobType  string        `gorm:"type:varchar(32);not null"`
-	Priority int           `gorm:"type:smallint;not null"`
-	Status   api.JobStatus `gorm:"type:varchar(32);not null"`
+	Name     string        `gorm:"type:varchar(64);default:''"`
+	JobType  string        `gorm:"type:varchar(32);default:''"`
+	Priority int           `gorm:"type:smallint;default:0"`
+	Status   api.JobStatus `gorm:"type:varchar(32);default:''"`
 
 	Settings StringInterfaceMap `gorm:"type:jsonb"`
 	Metadata StringStringMap    `gorm:"type:jsonb"`
@@ -51,14 +51,14 @@ type StringStringMap map[string]string
 
 type Task struct {
 	gorm.Model
-	UUID string `gorm:"type:char(36);not null;unique;index"`
+	UUID string `gorm:"type:char(36);default:'';unique;index"`
 
-	Name     string         `gorm:"type:varchar(64);not null"`
-	Type     string         `gorm:"type:varchar(32);not null"`
-	JobID    uint           `gorm:"not null"`
-	Job      *Job           `gorm:"foreignkey:JobID;references:ID;constraint:OnDelete:CASCADE;not null"`
-	Priority int            `gorm:"type:smallint;not null"`
-	Status   api.TaskStatus `gorm:"type:varchar(16);not null"`
+	Name     string         `gorm:"type:varchar(64);default:''"`
+	Type     string         `gorm:"type:varchar(32);default:''"`
+	JobID    uint           `gorm:"default:0"`
+	Job      *Job           `gorm:"foreignkey:JobID;references:ID;constraint:OnDelete:CASCADE"`
+	Priority int            `gorm:"type:smallint;default:50"`
+	Status   api.TaskStatus `gorm:"type:varchar(16);default:''"`
 
 	// Which worker is/was working on this.
 	WorkerID *uint
@@ -68,7 +68,7 @@ type Task struct {
 	Dependencies []*Task `gorm:"many2many:task_dependencies;constraint:OnDelete:CASCADE"`
 
 	Commands Commands `gorm:"type:jsonb"`
-	Activity string   `gorm:"type:varchar(255);not null;default:\"\""`
+	Activity string   `gorm:"type:varchar(255);default:''"`
 }
 
 type Commands []Command
diff --git a/internal/manager/persistence/workers.go b/internal/manager/persistence/workers.go
index e97b8199..6e77d064 100644
--- a/internal/manager/persistence/workers.go
+++ b/internal/manager/persistence/workers.go
@@ -32,18 +32,18 @@ import (
 
 type Worker struct {
 	gorm.Model
-	UUID   string `gorm:"type:char(36);not null;unique;index"`
-	Secret string `gorm:"type:varchar(255);not null"`
-	Name   string `gorm:"type:varchar(64);not null"`
+	UUID   string `gorm:"type:char(36);default:'';unique;index;default:''"`
+	Secret string `gorm:"type:varchar(255);default:''"`
+	Name   string `gorm:"type:varchar(64);default:''"`
 
-	Address         string           `gorm:"type:varchar(39);not null;index"` // 39 = max length of IPv6 address.
-	LastActivity    string           `gorm:"type:varchar(255);not null"`
-	Platform        string           `gorm:"type:varchar(16);not null"`
-	Software        string           `gorm:"type:varchar(32);not null"`
-	Status          api.WorkerStatus `gorm:"type:varchar(16);not null"`
-	StatusRequested api.WorkerStatus `gorm:"type:varchar(16);not null;default:''"`
+	Address         string           `gorm:"type:varchar(39);default:'';index"` // 39 = max length of IPv6 address.
+	LastActivity    string           `gorm:"type:varchar(255);default:''"`
+	Platform        string           `gorm:"type:varchar(16);default:''"`
+	Software        string           `gorm:"type:varchar(32);default:''"`
+	Status          api.WorkerStatus `gorm:"type:varchar(16);default:''"`
+	StatusRequested api.WorkerStatus `gorm:"type:varchar(16);default:''"`
 
-	SupportedTaskTypes string `gorm:"type:varchar(255);not null"` // comma-separated list of task types.
+	SupportedTaskTypes string `gorm:"type:varchar(255);default:''"` // comma-separated list of task types.
 }
 
 // TaskTypes returns the worker's supported task types as list of strings.