chore: initialize insar management system v2

backend/alembic/versions/0001_baseline.py

@@ -0,0 +1,30 @@
+"""baseline: 标记现有 schema 为 Alembic 管理起点
+
+此迁移为空操作（no-op）。数据库表结构已由应用启动时的 create_all 创建。
+首次引入 Alembic 时，请执行以下命令将当前数据库标记为此基线：
+
+    cd backend
+    alembic stamp head
+
+之后所有 schema 变更均通过 alembic revision --autogenerate 管理。
+
+Revision ID: 0001
+Revises:
+Create Date: 2026-02-19
+"""
+from typing import Sequence, Union
+
+revision: str = "0001"
+down_revision: Union[str, None] = None
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # 基线迁移：数据库已由 create_all 初始化，此处无需操作。
+    pass
+
+
+def downgrade() -> None:
+    # 基线无法回滚。
+    pass

backend/alembic/versions/0002_water_v2.py

@@ -0,0 +1,66 @@
+"""water_v2: 新增 sar_scene_geo 和 flood_detections 表
+
+Revision ID: 0002
+Revises: 0001
+Create Date: 2026-02-25
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0002"
+down_revision: Union[str, None] = "0001"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # 清理旧 water 表（如果存在）
+    op.execute("DROP TABLE IF EXISTS flood_events CASCADE")
+    op.execute("DROP TABLE IF EXISTS water_pairs CASCADE")
+    op.execute("DROP TABLE IF EXISTS water_masks CASCADE")
+
+    op.create_table(
+        "sar_scene_geo",
+        sa.Column("id", sa.Integer(), autoincrement=True, nullable=False),
+        sa.Column("radar_data_id", sa.Integer(), nullable=False),
+        sa.Column("geo_path", sa.String(), nullable=True),
+        sa.Column("pixel_size_m", sa.Float(), nullable=True),
+        sa.Column("status", sa.String(), nullable=False, server_default="PENDING"),
+        sa.Column("error_msg", sa.Text(), nullable=True),
+        sa.Column("created_at", sa.DateTime(), server_default=sa.text("now()"), nullable=True),
+        sa.Column("updated_at", sa.DateTime(), server_default=sa.text("now()"), nullable=True),
+        sa.ForeignKeyConstraint(["radar_data_id"], ["radar_data.id"]),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint("radar_data_id", name="uq_sar_scene_geo_radar"),
+    )
+    op.create_index("ix_sar_scene_geo_radar_data_id", "sar_scene_geo", ["radar_data_id"])
+    op.create_index("ix_sar_scene_geo_status", "sar_scene_geo", ["status"])
+
+    op.create_table(
+        "flood_detections",
+        sa.Column("id", sa.Integer(), autoincrement=True, nullable=False),
+        sa.Column("pre_scene_id", sa.Integer(), nullable=False),
+        sa.Column("post_scene_id", sa.Integer(), nullable=False),
+        sa.Column("output_dir", sa.String(), nullable=True),
+        sa.Column("classified_path", sa.String(), nullable=True),
+        sa.Column("flood_area_km2", sa.Float(), nullable=True),
+        sa.Column("stable_water_area_km2", sa.Float(), nullable=True),
+        sa.Column("status", sa.String(), nullable=False, server_default="PENDING"),
+        sa.Column("error_msg", sa.Text(), nullable=True),
+        sa.Column("created_at", sa.DateTime(), server_default=sa.text("now()"), nullable=True),
+        sa.Column("updated_at", sa.DateTime(), server_default=sa.text("now()"), nullable=True),
+        sa.ForeignKeyConstraint(["pre_scene_id"], ["sar_scene_geo.id"]),
+        sa.ForeignKeyConstraint(["post_scene_id"], ["sar_scene_geo.id"]),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint("pre_scene_id", "post_scene_id", name="uq_flood_detection_pair"),
+    )
+    op.create_index("ix_flood_detections_pre_scene_id", "flood_detections", ["pre_scene_id"])
+    op.create_index("ix_flood_detections_post_scene_id", "flood_detections", ["post_scene_id"])
+    op.create_index("ix_flood_detections_status", "flood_detections", ["status"])
+
+
+def downgrade() -> None:
+    op.drop_table("flood_detections")
+    op.drop_table("sar_scene_geo")