diff --git a/README.md b/README.md
index 45cc2b3..976f2d3 100644
--- a/README.md
+++ b/README.md
@@ -28,3 +28,8 @@ https://www.fma.gv.at/banken/
 * WPF
 * LINQ
 * SQLite
+
+
+# Links
+
+[PLZ](https://www.post.at/g/c/postlexikon)
diff --git a/herkunft.md b/herkunft.md
new file mode 100644
index 0000000..7a3c376
--- /dev/null
+++ b/herkunft.md
@@ -0,0 +1,40 @@
+
+# Herkunft
+
+[Kürzelliste für Weinformulare - Bundeskellereiinspektion](https://www.bundeskellereiinspektion.at/downloads/allgemein/kuerzel.pdf)
+
+[Weinbau in Österreich - Wikipedia](https://de.wikipedia.org/wiki/Weinbau_in_%C3%96sterreich#Weinbaugebiete_in_%C3%96sterreich)
+
+```
+AUSL - Ausland
+EUXX - Verschnitt von mehreren Weinen der EU
+OEST - Österreich
+    BLXX - Bergland
+        BLKA - Kärnten
+        BLOO - Oberösterreich
+        BLSB - Salzburg
+        BLTI - Tirol
+        BLVO - Vorarlberg
+    SLXX - Steirerland
+        SLST - Steiermark
+            SLSS - Südsteiermark
+            SLVL - Vulkanland Steiermark
+            SLWS - Weststeiermark
+    WLXX - Weinland
+        WIEN - Wien
+        WLNO - Niederösterreich
+            WLCA - Carnuntum
+            WLKA - Kamptal
+            WLKT - Kremstal
+            WLTH - Thermenregion
+            WLTT - Traisental
+            WLWA - Wachau
+            WLWG - Wagram
+            WLWV - Weinviertel
+        WLBL - Burgenland
+            WLNS - Neusiedlersee
+            WLLB - Leithaberg
+            WLRO - Rosalia
+            WLMB - Mittelburgenland
+            WLEB - Eisenberg
+```
diff --git a/sql/base.sql b/sql/base.sql
new file mode 100644
index 0000000..3b12e8e
--- /dev/null
+++ b/sql/base.sql
@@ -0,0 +1,72 @@
+
+CREATE TABLE country (
+    alpha2 TEXT    NOT NULL CHECK(LENGTH(alpha2) = 2),
+    alpha3 TEXT    NOT NULL CHECK(LENGTH(alpha3) = 3),
+    num    INTEGER NOT NULL CHECK(num >= 0),
+    name   TEXT    NOT NULL,
+
+    is_visible INTEGER NOT NULL CHECK(is_visible = TRUE OR is_visible = FALSE) DEFAULT TRUE,
+
+    CONSTRAINT pk_country PRIMARY KEY (alpha2),
+    CONSTRAINT sk_country_alpha3 UNIQUE (alpha3),
+    CONSTRAINT sk_country_numeric UNIQUE (num),
+    CONSTRAINT sk_country_name UNIQUE (name)
+) STRICT;
+
+CREATE TABLE AT_bundesland (
+    id     INTEGER NOT NULL CHECK(id >= 0),
+    short1 TEXT    NOT NULL,
+    short2 TEXT,
+    name   TEXT    NOT NULL,
+
+    CONSTRAINT pk_AT_bundesland PRIMARY KEY (id),
+    CONSTRAINT sk_AT_bundesland_short1 UNIQUE (short1),
+    CONSTRAINT sk_AT_bundesland_short2 UNIQUE (short2),
+    CONSTRAINT sk_AT_bundesland_name UNIQUE (name)
+) STRICT;
+
+CREATE TABLE AT_gemeinde (
+    gkz     INTEGER NOT NULL CHECK(gkz >= 10000 AND gkz <= 99999),
+    land_id INTEGER NOT NULL CHECK(land_id = gkz / 10000),
+    name    TEXT    NOT NULL,
+
+    CONSTRAINT pk_AT_gemeinde PRIMARY KEY (gkz),
+    CONSTRAINT fk_AT_gemeinde_AT_bundesland FOREIGN KEY (land_id) REFERENCES AT_bundesland (id)
+) STRICT;
+
+CREATE TABLE AT_ort (
+    okz  INTEGER NOT NULL CHECK(okz > 0),
+    gkz  INTEGER NOT NULL,
+    name TEXT    NOT NULL,
+
+    CONSTRAINT pk_AT_ort PRIMARY KEY (okz),
+    CONSTRAINT fk_AT_ort_AT_gemeinde FOREIGN KEY (gkz) REFERENCES AT_gemeinde (gkz)
+) STRICT;
+
+CREATE TABLE AT_plz (
+    plz  INTEGER NOT NULL CHECK(plz >= 1000 AND plz <= 9999),
+    okz  INTEGER NOT NULL,
+    name TEXT    NOT NULL,
+
+    CONSTRAINT pk_AT_plz PRIMARY KEY (plz, okz),
+    CONSTRAINT fk_AT_plz_AT_ort FOREIGN KEY (okz) REFERENCES AT_ort (okz)
+) STRICT;
+
+
+INSERT INTO country VALUES
+('AT', 'AUT',  40, 'Österreich',  TRUE),
+('DE', 'DEU', 276, 'Deutschland', FALSE),
+('CZ', 'CZE', 203, 'Tschechien',  FALSE),
+('HU', 'HUN', 348, 'Ungarn',      FALSE),
+('SK', 'SVK', 703, 'Slowakei',    FALSE);
+
+INSERT INTO AT_bundesland VALUES
+(1, 'B',  'Bgld.', 'Burgenland'),
+(2, 'K',  'Ktn.',  'Kärnten'),
+(3, 'N',  'NÖ',    'Niederösterreich'),
+(4, 'O',  'OÖ',    'Oberösterreich'),
+(5, 'S',  'Sbg.',  'Salzburg'),
+(6, 'St', 'Stmk.', 'Steiermark'),
+(7, 'T',   NULL,   'Tirol'),
+(8, 'V',  'Vbg.',  'Vorarlberg'),
+(9, 'W',   NULL,   'Wien');