diff --git a/codehawk/postgresql/db_init.sql b/codehawk/postgresql/db_init.sql
index 2a3517c..720153b 100644
--- a/codehawk/postgresql/db_init.sql
+++ b/codehawk/postgresql/db_init.sql
@@ -1,53 +1,57 @@
-CREATE TABLE IF NOT EXISTS code_chunks (
-    id BIGSERIAL PRIMARY KEY,
-    repo_id TEXT NOT NULL,
-    commit_sha TEXT NOT NULL,
-    file_path TEXT NOT NULL,
-    language TEXT NOT NULL DEFAULT 'python',
-    symbol TEXT NOT NULL,
-    qualified_symbol TEXT NOT NULL,
-    symbol_type TEXT NOT NULL,
-    parent_symbol TEXT,
-    start_line INTEGER NOT NULL,
-    end_line INTEGER NOT NULL,
-    start_col INTEGER,
-    end_col INTEGER,
-    signature TEXT,
-    docstring TEXT,
-    content TEXT NOT NULL,
-    content_hash TEXT NOT NULL,
-    metadata JSONB NOT NULL DEFAULT '{}'::jsonb,
-    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
-    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
-    CONSTRAINT code_chunks_line_range_check CHECK (start_line <= end_line),
-    CONSTRAINT code_chunks_col_range_check CHECK (
-        start_col IS NULL
-        OR end_col IS NULL
-        OR start_col <= end_col
-    ),
-    CONSTRAINT code_chunks_symbol_type_check CHECK (
-        symbol_type IN ('module', 'class', 'function', 'method', 'async_function', 'async_method')
-    ),
-    CONSTRAINT code_chunks_unique_content UNIQUE (
-        repo_id,
-        commit_sha,
-        file_path,
-        qualified_symbol,
-        start_line,
-        end_line,
-        content_hash
-    )
-);
-
-CREATE INDEX IF NOT EXISTS code_chunks_repo_commit_idx
-    ON code_chunks (repo_id, commit_sha);
-
-CREATE INDEX IF NOT EXISTS code_chunks_file_range_idx
-    ON code_chunks (repo_id, commit_sha, file_path, start_line, end_line);
-
-CREATE INDEX IF NOT EXISTS code_chunks_symbol_idx
-    ON code_chunks (repo_id, commit_sha, qualified_symbol);
-
+CREATE TABLE IF NOT EXISTS code_chunks (
+    id BIGSERIAL PRIMARY KEY,
+    repo_id TEXT NOT NULL,
+    commit_sha TEXT NOT NULL,
+    file_path TEXT NOT NULL,
+    language TEXT NOT NULL DEFAULT 'python',
+    symbol TEXT NOT NULL,
+    qualified_symbol TEXT NOT NULL,
+    symbol_type TEXT NOT NULL,
+    parent_symbol TEXT,
+    start_line INTEGER NOT NULL,
+    end_line INTEGER NOT NULL,
+    start_col INTEGER,
+    end_col INTEGER,
+    signature TEXT,
+    docstring TEXT,
+    content TEXT NOT NULL,
+    content_hash TEXT NOT NULL,
+    metadata JSONB NOT NULL DEFAULT '{}'::jsonb,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    CONSTRAINT code_chunks_line_range_check CHECK (start_line <= end_line),
+    CONSTRAINT code_chunks_col_range_check CHECK (
+        start_col IS NULL
+        OR end_col IS NULL
+        OR start_line < end_line
+        OR (
+            start_line == end_line AND
+            start_col <= end_col
+        )
+    ),
+    CONSTRAINT code_chunks_symbol_type_check CHECK (
+        symbol_type IN ('module', 'class', 'function', 'method', 'async_function', 'async_method')
+    ),
+    CONSTRAINT code_chunks_unique_content UNIQUE (
+        repo_id,
+        commit_sha,
+        file_path,
+        qualified_symbol,
+        start_line,
+        end_line,
+        content_hash
+    )
+);
+
+CREATE INDEX IF NOT EXISTS code_chunks_repo_commit_idx
+    ON code_chunks (repo_id, commit_sha);
+
+CREATE INDEX IF NOT EXISTS code_chunks_file_range_idx
+    ON code_chunks (repo_id, commit_sha, file_path, start_line, end_line);
+
+CREATE INDEX IF NOT EXISTS code_chunks_symbol_idx
+    ON code_chunks (repo_id, commit_sha, qualified_symbol);
+
 CREATE INDEX IF NOT EXISTS code_chunks_content_hash_idx
     ON code_chunks (content_hash);
 
@@ -78,7 +82,12 @@ CREATE TABLE IF NOT EXISTS code_references (
     CONSTRAINT code_references_col_range_check CHECK (
         start_col IS NULL
         OR end_col IS NULL
-        OR start_col <= end_col
+        OR end_line IS NULL
+        OR start_line < end_line
+        OR (
+            start_line = end_line AND
+            start_col <= end_col
+        )
     ),
     CONSTRAINT code_references_type_check CHECK (
         reference_type IN (
@@ -118,4 +127,4 @@ CREATE INDEX IF NOT EXISTS code_references_resolved_symbol_idx
     ON code_references (repo_id, commit_sha, resolved_symbol);
 
 CREATE INDEX IF NOT EXISTS code_references_target_chunk_idx
-    ON code_references (target_chunk_id);
+    ON code_references (target_chunk_id);
\ No newline at end of file