feat: add database constraints support and restructure schema parsing

- Add PrimaryKey, ForeignKey, and Index message types to protobuf schema
- Extend Table message with constraint fields (primary_key, foreign_keys, indexes)
- Refactor Database to CatalogBuilder with plugin::Catalog integration
- Add merge_catalog functionality for combining schema definitions
- Update schema parsing to populate constraint information from SQL DDL
- Migrate from HashMap-based storage to Vec-based plugin types
- Add runtime schema processing with CatalogBuilder integration

BREAKING CHANGE: Database struct replaced with CatalogBuilder, changes public API

Signed-off-by: Svetlin Ralchev <iamralch@users.noreply.github.com>

Author: iamralch

proto/codegen.proto

@@ -69,10 +69,33 @@ message Enum {
   string comment = 3;
 }
 
+message PrimaryKey {
+  string name = 1 [json_name = "name"];
+  repeated string columns = 2 [json_name = "columns"];
+}
+
+message ForeignKey {
+  string name = 1 [json_name = "name"];
+  repeated string columns = 2 [json_name = "columns"];
+  string referenced_table = 3 [json_name = "referenced_table"];
+  repeated string referenced_columns = 4 [json_name = "referenced_columns"];
+  string on_delete = 5 [json_name = "on_delete"];
+  string on_update = 6 [json_name = "on_update"];
+}
+
+message Index {
+  string name = 1 [json_name = "name"];
+  repeated string columns = 2 [json_name = "columns"];
+  bool unique = 3 [json_name = "unique"];
+}
+
 message Table {
   Identifier rel = 1;
   repeated Column columns = 2;
   string comment = 3;
+  PrimaryKey primary_key = 4 [json_name = "primary_key"];
+  repeated ForeignKey foreign_keys = 5 [json_name = "foreign_keys"];
+  repeated Index indexes = 6 [json_name = "indexes"];
 }
 
 message Identifier {

src/plugin.rs

@@ -89,6 +89,37 @@ pub struct Enum {
     #[prost(string, tag = "3")]
     pub comment: ::prost::alloc::string::String,
 }
+#[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
+pub struct PrimaryKey {
+    #[prost(string, tag = "1")]
+    pub name: ::prost::alloc::string::String,
+    #[prost(string, repeated, tag = "2")]
+    pub columns: ::prost::alloc::vec::Vec<::prost::alloc::string::String>,
+}
+#[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
+pub struct ForeignKey {
+    #[prost(string, tag = "1")]
+    pub name: ::prost::alloc::string::String,
+    #[prost(string, repeated, tag = "2")]
+    pub columns: ::prost::alloc::vec::Vec<::prost::alloc::string::String>,
+    #[prost(string, tag = "3")]
+    pub referenced_table: ::prost::alloc::string::String,
+    #[prost(string, repeated, tag = "4")]
+    pub referenced_columns: ::prost::alloc::vec::Vec<::prost::alloc::string::String>,
+    #[prost(string, tag = "5")]
+    pub on_delete: ::prost::alloc::string::String,
+    #[prost(string, tag = "6")]
+    pub on_update: ::prost::alloc::string::String,
+}
+#[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
+pub struct Index {
+    #[prost(string, tag = "1")]
+    pub name: ::prost::alloc::string::String,
+    #[prost(string, repeated, tag = "2")]
+    pub columns: ::prost::alloc::vec::Vec<::prost::alloc::string::String>,
+    #[prost(bool, tag = "3")]
+    pub unique: bool,
+}
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct Table {
     #[prost(message, optional, tag = "1")]
@@ -97,6 +128,12 @@ pub struct Table {
     pub columns: ::prost::alloc::vec::Vec<Column>,
     #[prost(string, tag = "3")]
     pub comment: ::prost::alloc::string::String,
+    #[prost(message, optional, tag = "4")]
+    pub primary_key: ::core::option::Option<PrimaryKey>,
+    #[prost(message, repeated, tag = "5")]
+    pub foreign_keys: ::prost::alloc::vec::Vec<ForeignKey>,
+    #[prost(message, repeated, tag = "6")]
+    pub indexes: ::prost::alloc::vec::Vec<Index>,
 }
 #[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
 pub struct Identifier {

src/runtime.rs

@@ -33,6 +33,7 @@
 //! ```
 
 use crate::plugin::{GenerateRequest, GenerateResponse};
+use crate::schema::CatalogBuilder;
 use prost::Message;
 use std::error::Error;
 use std::io::{Read, Write};
@@ -156,9 +157,26 @@ where
     let mut input = Vec::new();
     reader.read_to_end(&mut input)?;
 
-    let request = GenerateRequest::decode(&input[..])?;
-    let response = process(request)?;
+    let mut request = GenerateRequest::decode(&input[..])?;
+
+    if let Some(settings) = &request.settings {
+        if !settings.schema.is_empty() {
+            let mut builder = CatalogBuilder::new(settings.engine.as_str());
+
+            for item in &settings.schema {
+                let schema = std::fs::read_to_string(item)?;
+                builder.parse_sql(&schema)?;
+            }
+
+            if let Some(catalog) = request.catalog.take() {
+                builder.merge_catalog(catalog);
+            }
 
+            request.catalog = Some(builder.build());
+        }
+    }
+
+    let response = process(request)?;
     let mut output = Vec::new();
     response.encode(&mut output)?;