add database migration tooling with alembic

src/wce_crm/db.py

@@ -13,6 +13,7 @@ from wce_crm import constants
 from wce_crm import types as t
 
 
+# // declarations
 class SafeDateTime(TypeDecorator):
     """Cleans non-standard ISO strings before parsing."""
 
@@ -57,8 +58,8 @@ class UTCDateTime(TypeDecorator):
         return value
 
 
-md_crm = sql.MetaData()
-md_main = sql.MetaData()
+MD_CRM = sql.MetaData()
+MD_MAIN = sql.MetaData()
 ENGINE = sql.create_engine(f"sqlite:///{constants.Config.DB_PATH_MAIN}")
 
 # ---------- OLD "Kontaktliste" ----------
@@ -141,7 +142,7 @@ ENGINE = sql.create_engine(f"sqlite:///{constants.Config.DB_PATH_MAIN}")
 
 ext_crm_master: sql.Table = Table(
     "Master",
-    md_crm,
+    MD_CRM,
     Column("ma_id", sql.Integer, nullable=False, unique=True),
     Column("wce_id", sql.ForeignKey("Nutzer.wce_id")),
     Column("ma_unternehmensname", sql.Text, nullable=True),
@@ -218,7 +219,7 @@ DF_CRM_MASTER = get_ext_crm_master(constants.Config.DB_PATH_CRM)
 
 ext_crm_nutzer: sql.Table = Table(
     "Nutzer",
-    md_crm,
+    MD_CRM,
     Column("wce_id", sql.Integer, nullable=False, unique=True),
     Column("wce_name", sql.Text, nullable=True),
     Column("wce_vorname", sql.Text, nullable=True),
@@ -246,7 +247,7 @@ ext_crm_nutzer_schema: t.PolarsSchema = {
 
 ext_crm_contact_person: sql.Table = Table(
     "Ansprechpartner",
-    md_crm,
+    MD_CRM,
     Column("an_id", sql.Integer, nullable=False, unique=True),
     Column("ma_id", sql.ForeignKey("Master.ma_id")),
     Column("wce_id", sql.ForeignKey("Nutzer.wce_id")),
@@ -325,7 +326,7 @@ DF_CONTACT_PERSON = get_ext_crm_contact_person(constants.Config.DB_PATH_CRM)
 
 grunderfassung: sql.Table = Table(
     "grunderfassung",
-    md_main,
+    MD_MAIN,
     Column(
         "erfassung_id",
         sql.Integer,
@@ -398,4 +399,4 @@ grunderfassung: sql.Table = Table(
     Column("WeitereInfos__WI_meldung_institution", sql.Text, nullable=True),
 )
 
-md_main.create_all(ENGINE)
+MD_MAIN.create_all(ENGINE)