diff --git a/dns/migrations/001_initial.sql b/dns/migrations/001_initial.sql
index aec7346..cc6634c 100644
--- a/dns/migrations/001_initial.sql
+++ b/dns/migrations/001_initial.sql
@@ -12,10 +12,12 @@ CREATE INDEX idx_users_username ON users(username);
 CREATE TABLE IF NOT EXISTS invite_codes (
     id INT AUTO_INCREMENT PRIMARY KEY,
     code VARCHAR(32) UNIQUE NOT NULL,
-    created_by INTEGER REFERENCES users(id),
-    used_by INTEGER REFERENCES users(id),
+    created_by INTEGER,
+    used_by INTEGER,
     created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
-    used_at TIMESTAMP
+    used_at TIMESTAMP,
+    FOREIGN KEY (created_by) REFERENCES users(id),
+    FOREIGN KEY (used_by) REFERENCES users(id)
 );
 
 CREATE INDEX idx_invite_codes_code ON invite_codes(code);
@@ -23,10 +25,12 @@ CREATE INDEX idx_invite_codes_code ON invite_codes(code);
 CREATE TABLE IF NOT EXISTS domain_invite_codes (
     id INT AUTO_INCREMENT PRIMARY KEY,
     code VARCHAR(32) UNIQUE NOT NULL,
-    created_by INTEGER REFERENCES users(id),
-    used_by INTEGER REFERENCES users(id),
+    created_by INTEGER,
+    used_by INTEGER,
     created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
-    used_at TIMESTAMP
+    used_at TIMESTAMP,
+    FOREIGN KEY (created_by) REFERENCES users(id),
+    FOREIGN KEY (used_by) REFERENCES users(id)
 );
 
 CREATE INDEX idx_domain_invite_codes_code ON domain_invite_codes(code);
@@ -38,11 +42,12 @@ CREATE TABLE IF NOT EXISTS domains (
     name VARCHAR(100) NOT NULL,
     tld VARCHAR(20) NOT NULL,
     ip VARCHAR(255) NOT NULL,
-    user_id INTEGER REFERENCES users(id),
+    user_id INTEGER,
     status VARCHAR(20) DEFAULT 'pending',
     denial_reason TEXT,
     created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
-    UNIQUE(name, tld)
+    UNIQUE(name, tld),
+    FOREIGN KEY (user_id) REFERENCES users(id)
 );
 
 CREATE INDEX idx_domains_name_tld ON domains(name, tld);
@@ -51,13 +56,14 @@ CREATE INDEX idx_domains_status ON domains(status);
 
 CREATE TABLE IF NOT EXISTS dns_records (
     id INT AUTO_INCREMENT PRIMARY KEY,
-    domain_id INTEGER NOT NULL REFERENCES domains(id) ON DELETE CASCADE,
+    domain_id INTEGER NOT NULL,
     record_type VARCHAR(10) NOT NULL,
     name VARCHAR(255) NOT NULL DEFAULT '@', -- @ for root, or subdomain name
     value VARCHAR(1000) NOT NULL,
     ttl INTEGER DEFAULT 3600,
     priority INTEGER, -- For MX records
-    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    FOREIGN KEY (domain_id) REFERENCES domains(id) ON DELETE CASCADE
 );
 
 CREATE INDEX idx_dns_records_domain_type ON dns_records(domain_id, record_type);
diff --git a/dns/migrations/005_add_certificate_challenges.sql b/dns/migrations/005_add_certificate_challenges.sql
index 8cd48d9..abe0104 100644
--- a/dns/migrations/005_add_certificate_challenges.sql
+++ b/dns/migrations/005_add_certificate_challenges.sql
@@ -18,13 +18,14 @@ CREATE INDEX idx_certificate_challenges_expires_at ON certificate_challenges(exp
 CREATE TABLE IF NOT EXISTS issued_certificates (
     id INT AUTO_INCREMENT PRIMARY KEY,
     domain VARCHAR(255) NOT NULL,
-    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    user_id INTEGER NOT NULL,
     certificate_pem TEXT NOT NULL,
     private_key_pem TEXT NOT NULL,
     issued_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
     expires_at TIMESTAMP NOT NULL,
     revoked_at TIMESTAMP,
-    serial_number VARCHAR(255) UNIQUE NOT NULL
+    serial_number VARCHAR(255) UNIQUE NOT NULL,
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
 );
 
 CREATE INDEX idx_issued_certificates_domain ON issued_certificates(domain);
diff --git a/dns/migrations/007_cleanup_invalid_records.sql b/dns/migrations/007_cleanup_invalid_records.sql
index f0ff418..d96d29e 100644
--- a/dns/migrations/007_cleanup_invalid_records.sql
+++ b/dns/migrations/007_cleanup_invalid_records.sql
@@ -2,7 +2,8 @@
 DELETE FROM dns_records WHERE record_type NOT IN ('A', 'AAAA', 'CNAME', 'TXT');
 
 -- Now apply the constraint
-ALTER TABLE dns_records DROP CONSTRAINT dns_records_record_type_check;
+-- MySQL doesn't support DROP CONSTRAINT syntax for CHECK constraints
+-- ALTER TABLE dns_records DROP CONSTRAINT dns_records_record_type_check;
 
 -- MySQL doesn't support table-level CHECK constraints, using trigger instead
 DELIMITER //
diff --git a/dns/migrations/010_add_search_crawl_status.sql b/dns/migrations/010_add_search_crawl_status.sql
index edc1e99..2cd4181 100644
--- a/dns/migrations/010_add_search_crawl_status.sql
+++ b/dns/migrations/010_add_search_crawl_status.sql
@@ -1,12 +1,13 @@
 -- Search engine domain crawl status tracking
 CREATE TABLE IF NOT EXISTS domain_crawl_status (
-    domain_id INT PRIMARY KEY, FOREIGN KEY (domain_id) REFERENCES domains(id) ON DELETE CASCADE,
+    domain_id INT PRIMARY KEY,
     last_crawled_at TIMESTAMP,
     next_crawl_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
     crawl_status VARCHAR(20) DEFAULT 'pending',
     error_message TEXT,
     pages_found INTEGER DEFAULT 0,
-    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    FOREIGN KEY (domain_id) REFERENCES domains(id) ON DELETE CASCADE
 );
 
 CREATE INDEX idx_domain_crawl_status_next_crawl ON domain_crawl_status(next_crawl_at);