diff --git a/alembic/versions/665259cdfdc0_change_unique_constraint_to_partial_.py b/alembic/versions/665259cdfdc0_change_unique_constraint_to_partial_.py
new file mode 100644
index 0000000..dbd9743
--- /dev/null
+++ b/alembic/versions/665259cdfdc0_change_unique_constraint_to_partial_.py
@@ -0,0 +1,47 @@
+"""change unique constraint to partial index for company person linking table
+
+Revision ID: 665259cdfdc0
+Revises: 03d4f000f445
+Create Date: 2026-07-22 10:14:43.889298
+
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "665259cdfdc0"
+down_revision: Union[str, Sequence[str], None] = "03d4f000f445"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table("zuordnung_personen_unternehmen", schema=None) as batch_op:
+        batch_op.drop_constraint(batch_op.f("uq_un_id_pers_id"), type_="unique")
+        batch_op.create_index(
+            "uq_aktive_zuordnung",
+            ["un_id", "pers_id"],
+            unique=True,
+            sqlite_where=sa.text("gueltig_bis IS NULL"),
+        )
+
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table("zuordnung_personen_unternehmen", schema=None) as batch_op:
+        batch_op.drop_index(
+            "uq_aktive_zuordnung", sqlite_where=sa.text("gueltig_bis IS NULL")
+        )
+        batch_op.create_unique_constraint(
+            batch_op.f("uq_un_id_pers_id"), ["un_id", "pers_id"]
+        )
+
+    # ### end Alembic commands ###
diff --git a/src/wce_crm/db.py b/src/wce_crm/db.py
index 16350dc..af0734e 100644
--- a/src/wce_crm/db.py
+++ b/src/wce_crm/db.py
@@ -6,8 +6,8 @@ import re
 from pathlib import Path
 
 import polars as pl
-import sqlalchemy as sql
-from sqlalchemy import Column, String, Table, TypeDecorator, UniqueConstraint, event
+import sqlalchemy as sa
+from sqlalchemy import Column, Index, String, Table, TypeDecorator, event, sql
 
 from wce_crm import constants
 from wce_crm import types as t
@@ -37,7 +37,7 @@ class SafeDateTime(TypeDecorator):
 class UTCDateTime(TypeDecorator):
     """Safely coerces naive datetimes from SQLite into timezone-aware UTC."""
 
-    impl = sql.DateTime
+    impl = sa.DateTime
     cache_ok = True
 
     def process_bind_param(self, value, dialect):
@@ -58,9 +58,9 @@ class UTCDateTime(TypeDecorator):
         return value
 
 
-MD_CRM = sql.MetaData()
-MD_MAIN = sql.MetaData()
-ENGINE = sql.create_engine(f"sqlite:///{constants.Config.DB_PATH_MAIN}")
+MD_CRM = sa.MetaData()
+MD_MAIN = sa.MetaData()
+ENGINE = sa.create_engine(f"sqlite:///{constants.Config.DB_PATH_MAIN}")
 
 
 @event.listens_for(ENGINE, "connect")
@@ -71,33 +71,33 @@ def attach_second_db(dbapi_connection, connection_record):
     cursor.close()
 
 
-ext_crm_master: sql.Table = Table(
+ext_crm_master: Table = Table(
     "Master",
     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),
-    Column("ma_branche", sql.Text, nullable=True),
-    Column("ma_strasse", sql.Text, nullable=True),
-    Column("ma_hausnummer", sql.Text, nullable=True),
-    Column("ma_plz", sql.Text, nullable=True),
-    Column("ma_ort", sql.Text, nullable=True),
-    Column("ma_plz_postfach", sql.Text, nullable=True),
-    Column("ma_postfach", sql.Text, nullable=True),
-    Column("ma_website", sql.Text, nullable=True),
-    Column("ma_mail", sql.Text, nullable=True),
-    Column("ma_telefonnummer", sql.Text, nullable=True),
-    Column("ma_faxnummer", sql.Text, nullable=True),
+    Column("ma_id", sa.Integer, nullable=False, unique=True),
+    Column("wce_id", sa.ForeignKey("Nutzer.wce_id")),
+    Column("ma_unternehmensname", sa.Text, nullable=True),
+    Column("ma_branche", sa.Text, nullable=True),
+    Column("ma_strasse", sa.Text, nullable=True),
+    Column("ma_hausnummer", sa.Text, nullable=True),
+    Column("ma_plz", sa.Text, nullable=True),
+    Column("ma_ort", sa.Text, nullable=True),
+    Column("ma_plz_postfach", sa.Text, nullable=True),
+    Column("ma_postfach", sa.Text, nullable=True),
+    Column("ma_website", sa.Text, nullable=True),
+    Column("ma_mail", sa.Text, nullable=True),
+    Column("ma_telefonnummer", sa.Text, nullable=True),
+    Column("ma_faxnummer", sa.Text, nullable=True),
     Column("ma_ersteintrag_datum", SafeDateTime, nullable=True),
     Column("ma_aktualisierung_datum", SafeDateTime, nullable=True),
-    Column("ma_aktualisierung_nutzer", sql.Text, nullable=True),
-    Column("ma_sollprozess", sql.Text, nullable=True),
-    Column("ma_auslaendische_mitarbeiter", sql.Text, nullable=True),
-    Column("ma_quelle_information", sql.Text, nullable=True),
-    Column("ma_bemerkung", sql.Text, nullable=True),
-    Column("ma_kontakt", sql.Boolean, nullable=True),
-    Column("ma_schlagworte", sql.Text, nullable=True),
-    Column("ma_archiviert", sql.Boolean, nullable=True, default=False),
+    Column("ma_aktualisierung_nutzer", sa.Text, nullable=True),
+    Column("ma_sollprozess", sa.Text, nullable=True),
+    Column("ma_auslaendische_mitarbeiter", sa.Text, nullable=True),
+    Column("ma_quelle_information", sa.Text, nullable=True),
+    Column("ma_bemerkung", sa.Text, nullable=True),
+    Column("ma_kontakt", sa.Boolean, nullable=True),
+    Column("ma_schlagworte", sa.Text, nullable=True),
+    Column("ma_archiviert", sa.Boolean, nullable=True, default=False),
 )
 
 
@@ -141,26 +141,26 @@ def get_ext_crm_master(
     if not db_path.exists():
         raise FileNotFoundError(f"Database not found under >{db_path}<")
 
-    engine = sql.create_engine(f"sqlite:///{db_path}")
-    stmt = sql.select(ext_crm_master)
+    engine = sa.create_engine(f"sqlite:///{db_path}")
+    stmt = sa.select(ext_crm_master)
     return pl.read_database(stmt, engine, schema_overrides=ext_crm_master_schema)
 
 
 DF_CRM_MASTER = get_ext_crm_master(constants.Config.DB_PATH_CRM)
 
-ext_crm_nutzer: sql.Table = Table(
+ext_crm_nutzer: Table = Table(
     "Nutzer",
     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),
-    Column("wce_kuerzel", sql.Text, nullable=True),
-    Column("wce_passwort", sql.Text, nullable=True),
-    Column("wce_angelegt_am", sql.DateTime, nullable=True),
-    Column("wce_rolle", sql.Text, nullable=True),
-    Column("wce_angelegt_von", sql.Text, nullable=True),
-    Column("wce_aktiv", sql.Boolean, nullable=True),
-    Column("wce_letzter_login", sql.DateTime, nullable=True),
+    Column("wce_id", sa.Integer, nullable=False, unique=True),
+    Column("wce_name", sa.Text, nullable=True),
+    Column("wce_vorname", sa.Text, nullable=True),
+    Column("wce_kuerzel", sa.Text, nullable=True),
+    Column("wce_passwort", sa.Text, nullable=True),
+    Column("wce_angelegt_am", sa.DateTime, nullable=True),
+    Column("wce_rolle", sa.Text, nullable=True),
+    Column("wce_angelegt_von", sa.Text, nullable=True),
+    Column("wce_aktiv", sa.Boolean, nullable=True),
+    Column("wce_letzter_login", sa.DateTime, nullable=True),
 )
 
 ext_crm_nutzer_schema: t.PolarsSchema = {
@@ -176,31 +176,31 @@ ext_crm_nutzer_schema: t.PolarsSchema = {
     "wce_letzter_login": pl.Datetime,
 }
 
-ext_crm_contact_person: sql.Table = Table(
+ext_crm_contact_person: Table = Table(
     "Ansprechpartner",
     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")),
-    Column("st_id", sql.Integer, nullable=False),
-    Column("an_sachgebiet", sql.Text, nullable=True),
-    Column("an_anrede", sql.Text, nullable=True),
-    Column("an_titel", sql.Text, nullable=True),
-    Column("an_nachname", sql.Text, nullable=True),
-    Column("an_vorname", sql.Text, nullable=True),
-    Column("an_position", sql.Text, nullable=True),
-    Column("an_mail", sql.Text, nullable=True),
-    Column("an_festnetz", sql.Text, nullable=True),
-    Column("an_mobil", sql.Text, nullable=True),
-    Column("an_faxnummer", sql.Text, nullable=True),
-    Column("an_hauptansprechpartner", sql.Text, nullable=True),
-    Column("an_anrede_anschrift", sql.Text, nullable=True),
-    Column("an_bemerkung", sql.Text, nullable=True),
+    Column("an_id", sa.Integer, nullable=False, unique=True),
+    Column("ma_id", sa.ForeignKey("Master.ma_id")),
+    Column("wce_id", sa.ForeignKey("Nutzer.wce_id")),
+    Column("st_id", sa.Integer, nullable=False),
+    Column("an_sachgebiet", sa.Text, nullable=True),
+    Column("an_anrede", sa.Text, nullable=True),
+    Column("an_titel", sa.Text, nullable=True),
+    Column("an_nachname", sa.Text, nullable=True),
+    Column("an_vorname", sa.Text, nullable=True),
+    Column("an_position", sa.Text, nullable=True),
+    Column("an_mail", sa.Text, nullable=True),
+    Column("an_festnetz", sa.Text, nullable=True),
+    Column("an_mobil", sa.Text, nullable=True),
+    Column("an_faxnummer", sa.Text, nullable=True),
+    Column("an_hauptansprechpartner", sa.Text, nullable=True),
+    Column("an_anrede_anschrift", sa.Text, nullable=True),
+    Column("an_bemerkung", sa.Text, nullable=True),
     Column("an_aktualisierung_datum", SafeDateTime, nullable=True),
-    Column("an_aktualisierung_nutzer", sql.Text, nullable=True),
+    Column("an_aktualisierung_nutzer", sa.Text, nullable=True),
     Column("an_letztes_kontaktdatum", SafeDateTime, nullable=True),
     Column("an_ersteintrag_datum", SafeDateTime, nullable=True),
-    Column("an_archiviert", sql.Boolean, nullable=True, default=0),
+    Column("an_archiviert", sa.Boolean, nullable=True, default=0),
 )
 
 
@@ -242,8 +242,8 @@ def get_ext_crm_contact_person(
     if not db_path.exists():
         raise FileNotFoundError(f"Database not found under >{db_path}<")
 
-    engine = sql.create_engine(f"sqlite:///{db_path}")
-    stmt = sql.select(ext_crm_contact_person)
+    engine = sa.create_engine(f"sqlite:///{db_path}")
+    stmt = sa.select(ext_crm_contact_person)
     df = pl.read_database(stmt, engine, schema_overrides=ext_crm_contact_person_schema)
     df = df.with_columns(
         pl.col(pl.String).str.replace_all(r"[\r\t\n]", " ").str.strip_chars(" ")
@@ -255,43 +255,43 @@ def get_ext_crm_contact_person(
 # df_contact_person = get_ext_crm_contact_person(None)
 DF_CONTACT_PERSON = get_ext_crm_contact_person(constants.Config.DB_PATH_CRM)
 
-ext_crm_master_attach: sql.Table = Table(
+ext_crm_master_attach: Table = Table(
     "Master",
     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),
-    Column("ma_branche", sql.Text, nullable=True),
-    Column("ma_strasse", sql.Text, nullable=True),
-    Column("ma_hausnummer", sql.Text, nullable=True),
-    Column("ma_plz", sql.Text, nullable=True),
-    Column("ma_ort", sql.Text, nullable=True),
-    Column("ma_plz_postfach", sql.Text, nullable=True),
-    Column("ma_postfach", sql.Text, nullable=True),
-    Column("ma_website", sql.Text, nullable=True),
-    Column("ma_mail", sql.Text, nullable=True),
-    Column("ma_telefonnummer", sql.Text, nullable=True),
-    Column("ma_faxnummer", sql.Text, nullable=True),
+    Column("ma_id", sa.Integer, nullable=False, unique=True),
+    Column("wce_id", sa.ForeignKey("Nutzer.wce_id")),
+    Column("ma_unternehmensname", sa.Text, nullable=True),
+    Column("ma_branche", sa.Text, nullable=True),
+    Column("ma_strasse", sa.Text, nullable=True),
+    Column("ma_hausnummer", sa.Text, nullable=True),
+    Column("ma_plz", sa.Text, nullable=True),
+    Column("ma_ort", sa.Text, nullable=True),
+    Column("ma_plz_postfach", sa.Text, nullable=True),
+    Column("ma_postfach", sa.Text, nullable=True),
+    Column("ma_website", sa.Text, nullable=True),
+    Column("ma_mail", sa.Text, nullable=True),
+    Column("ma_telefonnummer", sa.Text, nullable=True),
+    Column("ma_faxnummer", sa.Text, nullable=True),
     Column("ma_ersteintrag_datum", SafeDateTime, nullable=True),
     Column("ma_aktualisierung_datum", SafeDateTime, nullable=True),
-    Column("ma_aktualisierung_nutzer", sql.Text, nullable=True),
-    Column("ma_sollprozess", sql.Text, nullable=True),
-    Column("ma_auslaendische_mitarbeiter", sql.Text, nullable=True),
-    Column("ma_quelle_information", sql.Text, nullable=True),
-    Column("ma_bemerkung", sql.Text, nullable=True),
-    Column("ma_kontakt", sql.Boolean, nullable=True),
-    Column("ma_schlagworte", sql.Text, nullable=True),
-    Column("ma_archiviert", sql.Boolean, nullable=True, default=False),
+    Column("ma_aktualisierung_nutzer", sa.Text, nullable=True),
+    Column("ma_sollprozess", sa.Text, nullable=True),
+    Column("ma_auslaendische_mitarbeiter", sa.Text, nullable=True),
+    Column("ma_quelle_information", sa.Text, nullable=True),
+    Column("ma_bemerkung", sa.Text, nullable=True),
+    Column("ma_kontakt", sa.Boolean, nullable=True),
+    Column("ma_schlagworte", sa.Text, nullable=True),
+    Column("ma_archiviert", sa.Boolean, nullable=True, default=False),
     schema="kontaktliste",
 )
 
 
-grunderfassung_unternehmen: sql.Table = Table(
+grunderfassung_unternehmen: Table = Table(
     "grunderfassung_unternehmen",
     MD_MAIN,
     Column(
         "un_id",
-        sql.Integer,
+        sa.Integer,
         primary_key=True,
         autoincrement=True,
     ),
@@ -313,20 +313,20 @@ grunderfassung_unternehmen: sql.Table = Table(
         default=lambda: datetime.datetime.now(datetime.UTC),
         onupdate=lambda: datetime.datetime.now(datetime.UTC),
     ),
-    Column("Metadaten_nutzer", sql.String(20), nullable=True),
-    Column("Grunderfassung_fallnummer", sql.Text, nullable=True),
-    Column("Grunderfassung_notiz", sql.Text, nullable=True),
-    Column("Partnersuche__kanal_aufmerksamkeit", sql.Text, nullable=True, default=None),
-    Column("Partnersuche__person_suche", sql.Integer, nullable=True, default=None),
-    Column("Partnersuche__un_suche", sql.Integer, nullable=True, default=None),
+    Column("Metadaten_nutzer", sa.String(20), nullable=True),
+    Column("Grunderfassung_fallnummer", sa.Text, nullable=True),
+    Column("Grunderfassung_notiz", sa.Text, nullable=True),
+    Column("Partnersuche__kanal_aufmerksamkeit", sa.Text, nullable=True, default=None),
+    Column("Partnersuche__person_suche", sa.Integer, nullable=True, default=None),
+    Column("Partnersuche__un_suche", sa.Integer, nullable=True, default=None),
 )
 
-grunderfassung_personen: sql.Table = Table(
+grunderfassung_personen: Table = Table(
     "grunderfassung_personen",
     MD_MAIN,
     Column(
         "pers_id",
-        sql.Integer,
+        sa.Integer,
         primary_key=True,
         autoincrement=True,
     ),
@@ -348,67 +348,67 @@ grunderfassung_personen: sql.Table = Table(
         default=lambda: datetime.datetime.now(datetime.UTC),
         onupdate=lambda: datetime.datetime.now(datetime.UTC),
     ),
-    Column("Metadaten_nutzer", sql.String(20), nullable=True),
-    Column("Metadaten_wiedereintrittsdatum", sql.Date, nullable=True, default=None),
-    Column("Arbeitserfahrung", sql.Text, nullable=True),
-    Column("Grunderfassung_fallnummer", sql.Text, nullable=True),
-    Column("Grunderfassung_notiz", sql.Text, nullable=True),
-    Column("HoehereBildung", sql.Text, nullable=True),
-    Column("Kontaktperson__KP_adresse", sql.Text, nullable=True),
-    Column("Kontaktperson__KP_anrede_anschrift", sql.Text, nullable=True),
-    Column("Kontaktperson__KP_email", sql.Text, nullable=True),
-    Column("Kontaktperson__KP_festnetznummer", sql.Text, nullable=True),
-    Column("Kontaktperson__KP_funktion_beziehung", sql.Text, nullable=True),
-    Column("Kontaktperson__KP_mobilfunknummer", sql.Text, nullable=True),
-    Column("Kontaktperson__KP_name", sql.Text, nullable=True),
+    Column("Metadaten_nutzer", sa.String(20), nullable=True),
+    Column("Metadaten_wiedereintrittsdatum", sa.Date, nullable=True, default=None),
+    Column("Arbeitserfahrung", sa.Text, nullable=True),
+    Column("Grunderfassung_fallnummer", sa.Text, nullable=True),
+    Column("Grunderfassung_notiz", sa.Text, nullable=True),
+    Column("HoehereBildung", sa.Text, nullable=True),
+    Column("Kontaktperson__KP_adresse", sa.Text, nullable=True),
+    Column("Kontaktperson__KP_anrede_anschrift", sa.Text, nullable=True),
+    Column("Kontaktperson__KP_email", sa.Text, nullable=True),
+    Column("Kontaktperson__KP_festnetznummer", sa.Text, nullable=True),
+    Column("Kontaktperson__KP_funktion_beziehung", sa.Text, nullable=True),
+    Column("Kontaktperson__KP_mobilfunknummer", sa.Text, nullable=True),
+    Column("Kontaktperson__KP_name", sa.Text, nullable=True),
     Column(
-        "Kontaktperson__KP_name_partner", sql.Text, nullable=True
+        "Kontaktperson__KP_name_partner", sa.Text, nullable=True
     ),  # TODO: check if needed when set by trigger
-    Column("Kontaktperson__KP_titel", sql.Text, nullable=True),
-    Column("Kontaktperson__KP_vorname", sql.Text, nullable=True),
-    Column("Projektrelevanz__relevanz", sql.Text, nullable=True),
-    Column("Projektrelevanz__foerderperiode", sql.Text, nullable=True),
-    Column("Schulbildung", sql.Text, nullable=True),
-    Column("Sprachkenntnisse", sql.Text, nullable=True),
-    Column("Stammdaten__PLZ", sql.Text, nullable=True),
-    Column("Stammdaten__anrede_anschrift", sql.Text, nullable=True),
-    Column("Stammdaten__anzahl_kinder__alter", sql.Text, nullable=True),
-    Column("Stammdaten__anzahl_kinder__anzahl", sql.Integer, nullable=True),
-    Column("Stammdaten__aufenthaltsort", sql.Text, nullable=True),
-    Column("Stammdaten__bundesland", sql.Text, nullable=True),
-    Column("Stammdaten__land", sql.Text, nullable=True),
-    Column("Stammdaten__email", sql.Text, nullable=True),
-    Column("Stammdaten__familienstand", sql.Text, nullable=True),
-    Column("Stammdaten__festnetznummer", sql.Text, nullable=True),
-    Column("Stammdaten__geburtsdatum", sql.Date, nullable=True),
-    Column("Stammdaten__hausnummer", sql.Text, nullable=True),
-    Column("Stammdaten__herkunftsland", sql.Text, nullable=True),
-    Column("Stammdaten__mobilfunknummer", sql.Text, nullable=True),
-    Column("Stammdaten__name", sql.Text, nullable=True),
-    Column("Stammdaten__ort", sql.Text, nullable=True),
-    Column("Stammdaten__rueckkehrer", sql.Boolean, nullable=True),
-    Column("Stammdaten__staatsangehoerigkeit", sql.Text, nullable=True),
-    Column("Stammdaten__strasse", sql.Text, nullable=True),
-    Column("Stammdaten__titel", sql.Text, nullable=True),
-    Column("Stammdaten__vorname", sql.Text, nullable=True),
-    Column("WeitereInfos__WI_arbeitsstatus", sql.Text, nullable=True),
-    Column("WeitereInfos__WI_aufenthaltstitel", sql.Text, nullable=True),
-    Column("WeitereInfos__WI_deutsch_sprache", sql.Text, nullable=True),
-    Column("WeitereInfos__WI_gueltigkeit_aufenthaltstitel", sql.Date, nullable=True),
-    Column("WeitereInfos__WI_meldung_institution", sql.Text, nullable=True),
+    Column("Kontaktperson__KP_titel", sa.Text, nullable=True),
+    Column("Kontaktperson__KP_vorname", sa.Text, nullable=True),
+    Column("Projektrelevanz__relevanz", sa.Text, nullable=True),
+    Column("Projektrelevanz__foerderperiode", sa.Text, nullable=True),
+    Column("Schulbildung", sa.Text, nullable=True),
+    Column("Sprachkenntnisse", sa.Text, nullable=True),
+    Column("Stammdaten__PLZ", sa.Text, nullable=True),
+    Column("Stammdaten__anrede_anschrift", sa.Text, nullable=True),
+    Column("Stammdaten__anzahl_kinder__alter", sa.Text, nullable=True),
+    Column("Stammdaten__anzahl_kinder__anzahl", sa.Integer, nullable=True),
+    Column("Stammdaten__aufenthaltsort", sa.Text, nullable=True),
+    Column("Stammdaten__bundesland", sa.Text, nullable=True),
+    Column("Stammdaten__land", sa.Text, nullable=True),
+    Column("Stammdaten__email", sa.Text, nullable=True),
+    Column("Stammdaten__familienstand", sa.Text, nullable=True),
+    Column("Stammdaten__festnetznummer", sa.Text, nullable=True),
+    Column("Stammdaten__geburtsdatum", sa.Date, nullable=True),
+    Column("Stammdaten__hausnummer", sa.Text, nullable=True),
+    Column("Stammdaten__herkunftsland", sa.Text, nullable=True),
+    Column("Stammdaten__mobilfunknummer", sa.Text, nullable=True),
+    Column("Stammdaten__name", sa.Text, nullable=True),
+    Column("Stammdaten__ort", sa.Text, nullable=True),
+    Column("Stammdaten__rueckkehrer", sa.Boolean, nullable=True),
+    Column("Stammdaten__staatsangehoerigkeit", sa.Text, nullable=True),
+    Column("Stammdaten__strasse", sa.Text, nullable=True),
+    Column("Stammdaten__titel", sa.Text, nullable=True),
+    Column("Stammdaten__vorname", sa.Text, nullable=True),
+    Column("WeitereInfos__WI_arbeitsstatus", sa.Text, nullable=True),
+    Column("WeitereInfos__WI_aufenthaltstitel", sa.Text, nullable=True),
+    Column("WeitereInfos__WI_deutsch_sprache", sa.Text, nullable=True),
+    Column("WeitereInfos__WI_gueltigkeit_aufenthaltstitel", sa.Date, nullable=True),
+    Column("WeitereInfos__WI_meldung_institution", sa.Text, nullable=True),
 )
 
-zuordnung_personen_unternehmen: sql.Table = Table(
+zuordnung_personen_unternehmen: Table = Table(
     "zuordnung_personen_unternehmen",
     MD_MAIN,
     Column(
         "id",
-        sql.Integer,
+        sa.Integer,
         primary_key=True,
         autoincrement=True,
     ),
-    Column("un_id", sql.ForeignKey("grunderfassung_unternehmen.un_id"), nullable=False),
-    Column("pers_id", sql.ForeignKey("grunderfassung_personen.pers_id"), nullable=False),
+    Column("un_id", sa.ForeignKey("grunderfassung_unternehmen.un_id"), nullable=False),
+    Column("pers_id", sa.ForeignKey("grunderfassung_personen.pers_id"), nullable=False),
     Column(
         "gueltig_ab",
         UTCDateTime,
@@ -420,23 +420,29 @@ zuordnung_personen_unternehmen: sql.Table = Table(
         UTCDateTime,
         nullable=True,
     ),
-    UniqueConstraint("un_id", "pers_id", name="uq_un_id_pers_id"),
+    Index(
+        "uq_aktive_zuordnung",
+        "un_id",
+        "pers_id",
+        unique=True,
+        sqlite_where=sql.text("gueltig_bis IS NULL"),
+    ),
 )
 
 
-beratung_vorgang: sql.Table = Table(
+beratung_vorgang: Table = Table(
     "beratung_vorgang",
     MD_MAIN,
     Column(
         "vorgang_id",
-        sql.Integer,
+        sa.Integer,
         primary_key=True,
         autoincrement=True,
     ),
-    Column("un_id", sql.ForeignKey("grunderfassung_unternehmen.un_id"), nullable=True),
-    Column("pers_id", sql.ForeignKey("grunderfassung_personen.pers_id"), nullable=True),
-    Column("titel", sql.Text, nullable=False),
-    Column("beratungs_typ", sql.String(20), nullable=False),
+    Column("un_id", sa.ForeignKey("grunderfassung_unternehmen.un_id"), nullable=True),
+    Column("pers_id", sa.ForeignKey("grunderfassung_personen.pers_id"), nullable=True),
+    Column("titel", sa.Text, nullable=False),
+    Column("beratungs_typ", sa.String(20), nullable=False),
     Column(
         "erstellt",
         UTCDateTime,
@@ -458,29 +464,29 @@ beratung_vorgang: sql.Table = Table(
 )
 
 
-beratung_einzelberatung: sql.Table = Table(
+beratung_einzelberatung: Table = Table(
     "beratung_einzelberatung",
     MD_MAIN,
     Column(
         "beratung_id",
-        sql.Integer,
+        sa.Integer,
         primary_key=True,
         autoincrement=True,
     ),
-    Column("vorgang_id", sql.ForeignKey("beratung_vorgang.vorgang_id"), nullable=False),
-    Column("nutzer_id", sql.Integer, nullable=False),
-    Column("nutzer_name", sql.String(20), nullable=False),
+    Column("vorgang_id", sa.ForeignKey("beratung_vorgang.vorgang_id"), nullable=False),
+    Column("nutzer_id", sa.Integer, nullable=False),
+    Column("nutzer_name", sa.String(20), nullable=False),
     Column(
         "zeitstempel",
         UTCDateTime,
         nullable=False,
         default=lambda: datetime.datetime.now(datetime.UTC),
     ),
-    Column("ansprechpartner", sql.Text, nullable=False),
-    Column("kommunikationsweg", sql.Text, nullable=False),
-    Column("thema_crm_matrix", sql.Text, nullable=True),
-    Column("anmerkungen", sql.Text, nullable=True),
-    Column("rueckmeldung", sql.Text, nullable=True),
+    Column("ansprechpartner", sa.Text, nullable=False),
+    Column("kommunikationsweg", sa.Text, nullable=False),
+    Column("thema_crm_matrix", sa.Text, nullable=True),
+    Column("anmerkungen", sa.Text, nullable=True),
+    Column("rueckmeldung", sa.Text, nullable=True),
     Column(
         "erstellt",
         UTCDateTime,