diff --git a/server/migrations/20250301093450_create_table_definitions.sql b/server/migrations/20250301093450_create_table_definitions.sql
index f75837f..591718e 100644
--- a/server/migrations/20250301093450_create_table_definitions.sql
+++ b/server/migrations/20250301093450_create_table_definitions.sql
@@ -2,11 +2,20 @@
 CREATE TABLE table_definitions (
     id BIGSERIAL PRIMARY KEY,
     deleted BOOLEAN NOT NULL DEFAULT FALSE,
-    firma TEXT NOT NULL,
     table_name TEXT NOT NULL UNIQUE,
     columns JSONB NOT NULL,
     indexes JSONB NOT NULL,
-    created_at TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP
+    created_at TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP,
+    profile_id BIGINT NOT NULL REFERENCES profiles(id) DEFAULT 1,
+    linked_table_id BIGINT REFERENCES table_definitions(id)
 );
 
-CREATE INDEX idx_table_definitions_table_name ON table_definitions (table_name);
+-- Create composite unique index for profile+table combination
+CREATE UNIQUE INDEX idx_table_definitions_profile_table
+    ON table_definitions (profile_id, table_name);
+
+-- Add self-referential foreign key constraint
+ALTER TABLE table_definitions
+    ADD CONSTRAINT fk_linked_table
+    FOREIGN KEY (linked_table_id)
+    REFERENCES table_definitions(id);
diff --git a/server/migrations/20250301142238_create_profiles.sql b/server/migrations/20250301142238_create_profiles.sql
new file mode 100644
index 0000000..ba2c9d4
--- /dev/null
+++ b/server/migrations/20250301142238_create_profiles.sql
@@ -0,0 +1,9 @@
+-- Add migration script here
+CREATE TABLE profiles (
+    id BIGSERIAL PRIMARY KEY,
+    name TEXT NOT NULL UNIQUE,
+    created_at TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP
+);
+
+-- Create default profile for existing data
+INSERT INTO profiles (name) VALUES ('default');