diff --git a/main.py b/main.py
index 6428ed1..81dbe2e 100644
--- a/main.py
+++ b/main.py
@@ -1,5 +1,5 @@
 from psycopg2 import connect
-from seed import main
+from src.seed import main
 
 if __name__ == '__main__':
     conn = connect(dbname='railway', user='postgres', password='8h9hxh5YeBwfqTCrxQQb',
diff --git a/src/sql.py b/src/sql.py
new file mode 100644
index 0000000..ca5d418
--- /dev/null
+++ b/src/sql.py
@@ -0,0 +1,35 @@
+from psycopg2._psycopg import cursor
+
+from types import Account, Posting, PostingFilter
+
+
+def add_account(cursor: cursor, data: Account) -> int:
+    """Adds an account to the database."""
+    cursor.execute('INSERT INTO Account'
+                   '(first_name, last_name, email)'
+                   'VALUES (%s, %s, %s)'
+                   'RETURNING id',
+                   (data.first_name, data.last_name, data.email))
+    return cursor.fetchone()[0]
+
+
+def add_posting(cursor: cursor, data: Posting) -> int:
+    """Adds a posting to the database."""
+    cursor.execute('INSERT INTO Posting'
+                   '(name, date, description, a, b, c)'
+                   'VALUES (%s, %s, %s, %s, %s, %s)'
+                   'RETURNING id',
+                   (data.name, data.date, data.description, data.a, data.b, data.c))
+    return cursor.fetchone()[0]
+
+
+def add_posting_filter(cursor: cursor, data: PostingFilter) -> int:
+    """Adds a posting filter to the database."""
+    b_lower, b_upper = data.b if data.b else (None, None)
+    c_lower, c_upper = data.c if data.c else (None, None)
+    cursor.execute('INSERT INTO PostingFilter'
+                   '(creator, name, expires, a, b_lower, b_upper, c_lower, c_upper)'
+                   'VALUES (%s, %s, %s, %s, %s, %s)'
+                   'RETURNING id',
+                   (data.creator, data.name, data.expires, data.a, b_lower, b_upper, c_lower, c_upper))
+    return cursor.fetchone()[0]
diff --git a/src/types.py b/src/types.py
new file mode 100644
index 0000000..d06ff67
--- /dev/null
+++ b/src/types.py
@@ -0,0 +1,32 @@
+from dataclasses import dataclass
+from datetime import datetime
+from typing import Optional, Tuple
+
+
+@dataclass
+class Posting:
+    name: str
+    date: datetime
+    description: str
+
+    a: bool
+    b: int
+    c: float
+
+
+@dataclass
+class PostingFilter:
+    creator: int
+    name: str
+    expires: datetime
+
+    a: Optional[bool]
+    b: Optional[Tuple[int, int]]
+    c: Optional[Tuple[float, float]]
+
+
+@dataclass
+class Account:
+    first_name: str
+    last_name: str
+    email: str