feat: SQLAlchemy 모델 및 스키마 파일 생성 완료

- database.py: PostgreSQL 연결 설정 및 세션 관리
- models.py: Project, File, Material SQLAlchemy 모델 정의
- schemas.py: Pydantic 요청/응답 스키마 정의
- 완전한 데이터베이스 연동 구조 완성

backend/app/models.py

@@ -0,0 +1,74 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, Text, Numeric, ForeignKey
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import relationship
+from datetime import datetime
+
+Base = declarative_base()
+
+class Project(Base):
+    __tablename__ = "projects"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    official_project_code = Column(String(50), unique=True, index=True)
+    project_name = Column(String(200), nullable=False)
+    client_name = Column(String(100))
+    design_project_code = Column(String(50))
+    design_project_name = Column(String(200))
+    is_code_matched = Column(Boolean, default=False)
+    matched_by = Column(String(100))
+    matched_at = Column(DateTime)
+    status = Column(String(20), default='active')
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow)
+    description = Column(Text)
+    notes = Column(Text)
+    
+    # 관계 설정
+    files = relationship("File", back_populates="project")
+
+class File(Base):
+    __tablename__ = "files"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    project_id = Column(Integer, ForeignKey("projects.id"))
+    filename = Column(String(255), nullable=False)
+    original_filename = Column(String(255), nullable=False)
+    file_path = Column(String(500), nullable=False)
+    revision = Column(String(20), default='Rev.0')
+    upload_date = Column(DateTime, default=datetime.utcnow)
+    uploaded_by = Column(String(100))
+    file_type = Column(String(10))
+    file_size = Column(Integer)
+    is_active = Column(Boolean, default=True)
+    
+    # 관계 설정
+    project = relationship("Project", back_populates="files")
+    materials = relationship("Material", back_populates="file")
+
+class Material(Base):
+    __tablename__ = "materials"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    file_id = Column(Integer, ForeignKey("files.id"))
+    line_number = Column(Integer)
+    original_description = Column(Text, nullable=False)
+    classified_category = Column(String(50))
+    classified_subcategory = Column(String(100))
+    material_grade = Column(String(50))
+    schedule = Column(String(20))
+    size_spec = Column(String(50))
+    quantity = Column(Numeric(10, 3), nullable=False)
+    unit = Column(String(10), nullable=False)
+    drawing_name = Column(String(100))
+    area_code = Column(String(20))
+    line_no = Column(String(50))
+    classification_confidence = Column(Numeric(3, 2))
+    is_verified = Column(Boolean, default=False)
+    verified_by = Column(String(100))
+    verified_at = Column(DateTime)
+    drawing_reference = Column(String(100))
+    notes = Column(Text)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    
+    # 관계 설정
+    file = relationship("File", back_populates="materials")