Database Schema Code Generation (orionc Enhancement)

Goal

Generate C struct definitions from .orion database schemas, making the schema the single source of truth for both the database implementation and application code.

Status

✅ .orion schema updated with length attributes for strings ✅ Mock generated header created (build/generated/examples/socialfeed/socialfeed.h) ✅ db_simple_xml.h updated to include generated header ✅ All generated code consolidated into single socialfeed.h file ⏳ orionc compiler needs database schema parsing support

Schema Example (socialfeed.orion)

<database name="db" class="SimpleXMLDatabase" source="socialfeed_seed.xml">
  <table name="authors" model="author">
    <field name="id" type="integer" key="YES"/>
    <field name="name" type="string" length="64"/>
    <field name="avatar" type="string" length="256"/>
  </table>
  
  <table name="posts" model="post">
    <field name="id" type="integer" key="YES"/>
    <field name="author_id" type="integer" relation="authors.id"/>
    <field name="title" type="string" length="256"/>
    <field name="body" type="string" length="2048"/>
    <field name="like_count" type="integer"/>
    <field name="comment_count" type="integer"/>
  </table>
</database>

Generated Output (socialfeed.h)

Single generated header contains everything from .orion:

• Menu/toolbar IDs from <menus> and <toolbars>
• Form definitions from <forms>
• Database schema from <database>

// Generated by orionc from socialfeed.orion
#ifndef __SOCIALFEED_GENERATED_H__
#define __SOCIALFEED_GENERATED_H__

// Menu IDs
enum {
  ID_FILE_QUIT = 1000,
  ID_POST_NEW,
  // ...
};

// Table identifiers
enum {
  TABLE_AUTHORS = 0,
  TABLE_POSTS,
  TABLE_COMMENTS,
  TABLE_COUNT
};

// Generated structs (from <database> schema)
typedef struct author_s {
  int32_t id;
  char name[64];
  char avatar[256];
} author_t;

typedef struct post_s {
  int32_t id;
  int32_t author_id;
  char title[256];
  char body[2048];
  int32_t like_count;
  int32_t comment_count;
} post_t;

// Field bindings for DDX (auto-generated from schema)
extern const db_field_msg_binding_t author_bindings[];
extern const db_field_msg_binding_t post_bindings[];
extern const db_api_def_t socialfeed_database_api;

// Form definitions
extern const form_def_t socialfeed_main_window_form;
extern const form_def_t socialfeed_new_post_form;
// ...

#endif // __SOCIALFEED_GENERATED_H__

Type Mapping

.orion type	C type	Notes
integer	int32_t	Fixed-size for portability
string with length="N"	char[N]	Fixed-size buffer
boolean	bool	From <stdbool.h>
float	float	Single precision
double	double	Double precision

Field Attributes

• name — Field identifier (required)
• type — Data type (required)
• length — String buffer size (required for type="string")
• key="YES" — Primary key marker
• relation="table.field" — Foreign key relationship

orionc Implementation Tasks

1. Parse <database> Elements

• Extract database name, class, source path
• Enumerate <table> children

2. Parse <table> Elements

• Extract table name, model name
• Generate TABLE_* enum constants
• Enumerate <field> children

3. Parse <field> Elements

• Map XML type to C type
• Handle length attribute for strings
• Preserve key and relation as comments

4. Generate Struct Definitions

• Output typedef struct {name}_s { ... } {name}_t;
• Use int32_t for integers (fixed-size)
• Use char[N] for strings with declared length

5. Generate Field Bindings

• Create db_field_msg_binding_t arrays from schema
• Map field names to column IDs (COL_* enums)
• Export as extern const arrays

6. Generate Database API Metadata

• Create db_api_def_t struct with all tables
• Include table count, bindings arrays
• Export for tableview/inspector use

Benefits

✅ Single source of truth — Schema defined once in .orion ✅ Zero duplication — No manual struct definitions ✅ Type safety — Compiler validates field access ✅ Auto-sync — Database and app share same definitions ✅ IDE support — Autocomplete from generated structs ✅ Consistency — Field bindings generated from same schema

Migration Path

1. Add length attributes to existing schemas ✅
2. Create mock generated headers ✅
3. Update database implementations to include generated headers ✅
4. Implement orionc database parsing ⏳
5. Test generated code compiles ⏳
6. Remove manual struct definitions ⏳

Usage After Generation

// Application code includes the generated header
#include "build/generated/examples/socialfeed/socialfeed.h"

// Structs available automatically:
author_t author = { .name = "Alice", .avatar = "alice.png" };
post_t post = { .title = "Hello", .body = "World" };

// Table IDs from generated enum:
send_db_message(db, dbInsert, TABLE_AUTHORS, &author);

// Field bindings auto-available:
tableview_params_t params = {
  .db = db,
  .table_id = TABLE_POSTS,
  .field_names = (const char *[]){"title", "author", "like_count", NULL},
};

Related Files

• examples/socialfeed/socialfeed.orion — Schema definitions
• build/generated/examples/socialfeed/socialfeed.h — Generated header (menus, forms, database)
• examples/socialfeed/socialfeed.h — App header (includes generated header)
• examples/socialfeed/db_simple_xml.h — Database proc header
• examples/socialfeed/db_simple_xml.c — Database implementation
• tools/orionc.c — Compiler (needs database parsing)