fix: added examples for table extensions and fields mods

Author: fstagni

extensions/gubbins/gubbins-db/src/gubbins/db/sql/jobs/schema.py

@@ -1,17 +1,58 @@
 from diracx.db.sql.job.db import JobDBBase
+from diracx.db.sql.job.schema import InputData, Jobs
 from diracx.db.sql.utils import Column
 from sqlalchemy import (
     ForeignKey,
+    Index,
     Integer,
     String,
+    Text,
 )
 
 
+# Create a new external table for Gubbins-specific categories
+class GubbinsCategories(JobDBBase):
+    """External table for Gubbins-specific categories"""
+
+    __tablename__ = "GubbinsCategories"
+
+    category_id = Column("CategoryID", Integer, primary_key=True, autoincrement=True)
+    category_name = Column("CategoryName", String(255), nullable=False)
+    description = Column("Description", Text, default="")
+
+    __table_args__ = (Index("CategoryName", "CategoryName"),)
+
+
+# Create a new Jobs table with modified schema (replacing the original)
+class GubbinsJobs(Jobs):
+    """Custom Jobs table with modified column specifications and foreign key to GubbinsCategories"""
+
+    __tablename__ = "Jobs"
+
+    # Modified: job_name with VARCHAR(512) instead of VARCHAR(128)
+    job_name = Column("JobName", String(512), default="Unknown")
+
+    # New foreign key constraint to GubbinsCategories table
+    category_id = Column(
+        "CategoryID", Integer, ForeignKey("GubbinsCategories.CategoryID")
+    )
+
+
+# Extended InputData table with Adler checksum column
+class GubbinsInputData(InputData):
+    """Extended InputData table with Adler checksum support"""
+
+    __tablename__ = "InputData"
+
+    # New column for Adler checksum
+    adler_checksum = Column("AdlerChecksum", String(75), nullable=True)
+
+
 # You need to inherit from the declarative_base of the parent DB
 class GubbinsInfo(JobDBBase):
     """An extra table with respect to Vanilla diracx JobDB"""
 
-    __tablename__ = "GubbinsJobs"
+    __tablename__ = "GubbinsInfo"
 
     job_id = Column(
         "JobID", Integer, ForeignKey("Jobs.JobID", ondelete="CASCADE"), primary_key=True