diff --git a/services/blob/src/database/mod.rs b/services/blob/src/database/mod.rs
--- a/services/blob/src/database/mod.rs
+++ b/services/blob/src/database/mod.rs
@@ -1,2 +1,3 @@
 pub mod errors;
 pub mod old;
+pub mod types;
diff --git a/services/blob/src/database/types.rs b/services/blob/src/database/types.rs
new file mode 100644
--- /dev/null
+++ b/services/blob/src/database/types.rs
@@ -0,0 +1,160 @@
+use aws_sdk_dynamodb::types::AttributeValue;
+use chrono::{DateTime, Utc};
+use derive_more::Constructor;
+use std::collections::HashMap;
+
+use crate::{
+  constants::{db::*, BLOB_S3_BUCKET_NAME},
+  s3::S3Path,
+};
+
+use super::errors::Error as DBError;
+
+/// Represents a database row in the DynamoDB SDK format
+pub(super) type RawAttributes = HashMap<String, AttributeValue>;
+/// A convenience Result type for database operations
+pub(super) type DBResult<T> = Result<T, DBError>;
+
+/// Represents a type-safe version of a DynamoDB blob table item.
+/// Each row can be either a blob item or a holder assignment.
+///
+/// It implements the `TryFrom` trait to convert from raw DynamoDB
+/// `AttributeValue`s to the type-safe version.
+pub enum DBRow {
+  BlobItem(BlobItemRow),
+  HolderAssignment(HolderAssignmentRow),
+}
+
+impl TryFrom<RawAttributes> for DBRow {
+  type Error = DBError;
+
+  #[allow(unused)]
+  fn try_from(attributes: RawAttributes) -> Result<Self, Self::Error> {
+    todo!()
+  }
+}
+
+/// Represents an input payload for inserting a blob item into the database.
+/// This contains only the business logic related attributes
+#[derive(Debug)]
+pub struct BlobItemInput {
+  pub blob_hash: String,
+  pub s3_path: S3Path,
+}
+
+impl BlobItemInput {
+  pub fn new(blob_hash: impl Into<String>) -> Self {
+    let blob_hash: String = blob_hash.into();
+    BlobItemInput {
+      blob_hash: blob_hash.clone(),
+      s3_path: S3Path {
+        bucket_name: BLOB_S3_BUCKET_NAME.into(),
+        object_name: blob_hash,
+      },
+    }
+  }
+}
+
+/// A struct representing a blob item row in the table in a type-safe way
+///
+/// It implements the `TryFrom` trait to convert from raw DynamoDB
+/// `AttributeValue`s to the type-safe version.
+#[derive(Debug)]
+pub struct BlobItemRow {
+  pub blob_hash: String,
+  pub s3_path: S3Path,
+  pub unchecked: bool,
+  pub created_at: DateTime<Utc>,
+  pub last_modified: DateTime<Utc>,
+}
+
+impl TryFrom<RawAttributes> for BlobItemRow {
+  type Error = DBError;
+
+  #[allow(unused)]
+  fn try_from(mut attributes: RawAttributes) -> Result<Self, Self::Error> {
+    todo!()
+  }
+}
+
+/// A struct representing a holder assignment table row in a type-safe way
+///
+/// It implements the `TryFrom` trait to convert from raw DynamoDB
+/// `AttributeValue`s to the type-safe version.
+#[derive(Debug)]
+pub struct HolderAssignmentRow {
+  pub blob_hash: String,
+  pub holder: String,
+  pub unchecked: bool,
+  pub created_at: DateTime<Utc>,
+  pub last_modified: DateTime<Utc>,
+}
+
+impl TryFrom<RawAttributes> for HolderAssignmentRow {
+  type Error = DBError;
+
+  #[allow(unused)]
+  fn try_from(mut attributes: RawAttributes) -> Result<Self, Self::Error> {
+    todo!()
+  }
+}
+
+/// Represents a composite primary key for a DynamoDB table row
+///
+/// It implements `TryFrom` and `Into` traits to conveniently use it
+/// in DynamoDB queries
+#[derive(Clone, Constructor, Debug)]
+pub struct PrimaryKey {
+  pub blob_hash: String,
+  pub holder: String,
+}
+
+impl PrimaryKey {
+  /// Creates a primary key for a row containing a blob item data
+  /// Rows queried by primary keys created by this function will
+  /// be of type `BlobItemRow`
+  pub fn for_blob_item(blob_hash: impl Into<String>) -> Self {
+    PrimaryKey {
+      blob_hash: blob_hash.into(),
+      holder: BLOB_ITEM_ROW_HOLDER_VALUE.to_string(),
+    }
+  }
+}
+
+impl TryFrom<RawAttributes> for PrimaryKey {
+  type Error = DBError;
+
+  #[allow(unused)]
+  fn try_from(mut attributes: RawAttributes) -> Result<Self, Self::Error> {
+    todo!()
+  }
+}
+
+// useful for convenient calls:
+// ddb.get_item().set_key(Some(partition_key.into()))
+impl Into<RawAttributes> for PrimaryKey {
+  fn into(self) -> RawAttributes {
+    todo!()
+  }
+}
+
+/// Represents possible values for the `unchecked` attribute value
+pub enum UncheckedKind {
+  Blob,
+  Holder,
+}
+
+impl UncheckedKind {
+  pub fn str_value(&self) -> &'static str {
+    match self {
+      UncheckedKind::Blob => "blob",
+      UncheckedKind::Holder => "holder",
+    }
+  }
+}
+
+impl Into<AttributeValue> for UncheckedKind {
+  fn into(self) -> AttributeValue {
+    AttributeValue::S(self.str_value().to_string())
+  }
+}