use db2 dsn in tests and readme default configuration

.gitignore

@@ -7,4 +7,5 @@ testext
 test/python/__pycache__/
 .Rhistory
 .clangd
-.data
+.odbc.ini
+.odbcinst.ini

README.md

@@ -4,9 +4,12 @@ A DuckDB extension to read data directly from databases supporting the ODBC inte
 
 ### odbc_scan
 
+```shell
+ODBCSYSINI=${PWD} ODBCINSTINI=.odbcinst.ini ODBCINI=.odbc.ini ./build/release/duckdb
+```
 ```duckdb
 D select * from odbc_scan(
-    'Driver=/nix/store/py6m0q4ij50pwjk6a5f18qhhahrvf2sk-db2-driver-11.5.8/lib/libdb2.so;Hostname=localhost;Database=odbctest;Uid=db2inst1;Pwd=password;Port=50000',
+    'Driver={db2 odbctest};Hostname=localhost;Database=odbctest;Uid=db2inst1;Pwd=password;Port=50000',
     'DB2INST1',
     'PEOPLE'
 );
@@ -42,12 +45,9 @@ This extension is tested and known to work with the ODBC drivers of the followin
 If you have tested the extension against other databases let us know by opening an [issue](https://github.com/rupurt/odbc-scanner-duckdb-extension/issues/new)
 or creating a pull request with a set of tests.
 
-## Supported DSN Formats
+## Connection String and DSN Formats
 
-### Connection Strings
-
-- IBM Db2  - `Driver=/nix/store/py6m0q4ij50pwjk6a5f18qhhahrvf2sk-db2-driver-11.5.8/lib/libdb2.so;Hostname=localhost;Database=odbctest;Uid=db2inst1;Pwd=password;Port=50000`
-- Postgres - `Driver=/opt/homebrew/Cellar/psqlodbc/15.00.0000/lib/psqlodbca.so;Server=localhost;Database=odbc_test;Uid=postgres;Pwd=password;Port=5432`
+For a full list of supported values read the [connection string](./docs/ODBC_CONNECTION_STRING_AND_DSN_FORMATS.md) documentation.
 
 ## Development
 
@@ -75,6 +75,13 @@ nix run .#build
 ./build/release/duckdb
 ```
 
+To use ODBC DSN's with driver paths managed by the `odbc-drivers-nix` flake run the generate nix apps.
+
+```shell
+nix run .#generate-odbc-ini
+nix run .#generate-odbcinst-ini
+```
+
 ## Test
 
 Run the official DuckDB `cmake` builder with `nix` to ensure `unixodbc` is linked correctly

docs/ODBC_CONNECTION_STRING_AND_DSN_FORMATS.md

@@ -0,0 +1,33 @@
+# ODBC Connection String and DSN Formats
+
+`odbc-scanner-duckdb` supports standard ODBC connection string and DSN formats. A detailed list can be obtained
+from [connectionstrings.com](https://www.connectionstrings.com).
+
+## Find the Path to your Nix managed ODBC Driver
+
+```shell
+nix run .#odbc-driver-paths
+db2 /nix/store/6flbacf9h5bk09iw37b7sncgjn9mdkwj-db2-odbc-driver-11.5.8/lib/libdb2.so
+```
+
+## DSN's
+
+### Db2
+
+```odbc.ini
+[db2 odbctest]
+Driver = db2
+```
+
+```odbcinst.ini
+[db2]
+Driver = ${DB2_DRIVER_PATH}
+```
+
+## Connection Strings
+
+### Db2
+
+```
+Driver=/nix/store/py6m0q4ij50pwjk6a5f18qhhahrvf2sk-db2-driver-11.5.8/lib/libdb2.so;Hostname=localhost;Database=odbctest;Uid=db2inst1;Pwd=password;Port=50000
+```

flake.nix

@@ -4,22 +4,35 @@
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
     flake-utils.url = "github:numtide/flake-utils";
+    odbc-drivers.url = "github:rupurt/odbc-drivers-nix";
   };
 
   outputs = {
     flake-utils,
-    nixpkgs,
+    odbc-drivers,
     ...
   }: let
     systems = ["x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin"];
     outputs = flake-utils.lib.eachSystem systems (system: let
-      pkgs = import nixpkgs {
-        inherit system;
-        # config = { allowUnfree = true; };
-      };
+      # use old version of nix packages that builds against glibc 2.35
+      pkgs =
+        import (builtins.fetchGit {
+          name = "nixpkgs-with-glibc-2.35-224";
+          url = "https://github.com/nixos/nixpkgs";
+          ref = "refs/heads/nixpkgs-unstable";
+          rev = "8ad5e8132c5dcf977e308e7bf5517cc6cc0bf7d8";
+        }) {
+          inherit system;
+          overlays = [
+            odbc-drivers.overlay
+          ];
+        };
+      stdenv = pkgs.llvmPackages_15.stdenv;
     in rec {
       # packages exported by the flake
-      packages = {};
+      packages = {
+        db2-odbc-driver = pkgs.db2-odbc-driver {};
+      };
 
       # nix run
       apps = {
@@ -30,6 +43,23 @@
               envsubst < ./templates/.clangd.template > .clangd
           '');
         };
+        generate-odbc-ini = {
+          type = "app";
+          program = toString (pkgs.writeScript "generate-odbc-ini" ''
+            cp ./templates/.odbc.ini.template .odbc.ini
+          '');
+        };
+        generate-odbcinst-ini = {
+          type = "app";
+          program = toString (pkgs.writeScript "generate-odbcinst-ini" ''
+            DB2_DRIVER_PATH=${packages.db2-odbc-driver}/lib/${if stdenv.isDarwin then "libdb2.dylib" else "libdb2.so"} \
+              envsubst < ./templates/.odbcinst.ini.template > .odbcinst.ini
+          '');
+        };
+        ls-odbc-driver-paths = {
+          type = "app";
+          program = toString (pkgs.writeScript "ls-odbc-driver-paths" ''
+            echo "db2 ${packages.db2-odbc-driver}/lib/${if stdenv.isDarwin then "libdb2.dylib" else "libdb2.so"}"
           '');
         };
         load-db2-schema = {
@@ -47,18 +77,18 @@
                 gnumake
                 cmake
                 ninja
-                llvmPackages_16.clang
                 openssl
-                # unixODBCDrivers.msodbcsql17
-                unixODBCDrivers.psql
-                # unixODBCDrivers.mariadb
+                packages.db2-odbc-driver
               ]
             )}:$PATH"
-            export CC=${pkgs.llvmPackages_16.clang}/bin/clang
-            export CXX=${pkgs.llvmPackages_16.clang}/bin/clang++
+            export CC=${stdenv.cc}/bin/clang
+            export CXX=${stdenv.cc}/bin/clang++
 
             make \
               GEN=ninja \
+              ODBCSYSINI=$PWD \
+              ODBCINSTINI=.odbcinst.ini \
+              ODBCINI=$PWD/.odbc.ini \
               test CLIENT_FLAGS="-DODBC_CONFIG=${pkgs.unixODBC}/bin/odbc_config"
           '');
         };
@@ -71,15 +101,12 @@
                 gnumake
                 cmake
                 ninja
-                llvmPackages_16.clang
                 openssl
-                # unixODBCDrivers.msodbcsql17
-                unixODBCDrivers.psql
-                # unixODBCDrivers.mariadb
+                packages.db2-odbc-driver
               ]
             )}:$PATH"
-            export CC=${pkgs.llvmPackages_16.clang}/bin/clang
-            export CXX=${pkgs.llvmPackages_16.clang}/bin/clang++
+            export CC=${stdenv.cc}/bin/clang
+            export CXX=${stdenv.cc}/bin/clang++
 
             make \
               GEN=ninja \
@@ -98,14 +125,17 @@
           pkgs.git
           pkgs.gnumake
           pkgs.cmake
+          # faster cmake builds
           pkgs.ninja
-          pkgs.llvmPackages_16.clang
+          # clangd lsp
+          pkgs.llvmPackages_15.bintools
+          pkgs.llvmPackages_15.clang
+          pkgs.envsubst
           pkgs.openssl
           pkgs.unixODBC
-          # pkgs.unixODBCDrivers.msodbcsql17
-          pkgs.unixODBCDrivers.psql
-          # pkgs.unixODBCDrivers.mariadb
+          # psql cli
           pkgs.postgresql_15
+          packages.db2-odbc-driver
         ];
       };
     });

src/include/odbc.hpp

@@ -294,15 +294,15 @@ struct OdbcConnection {
                       " native=" + std::to_string(diagnostics->native));
     }
   }
-  void Dial(string dsn) {
-    auto conn_str_in_len = (SQLSMALLINT)dsn.length();
+  void Dial(string connection_string) {
+    auto conn_str_in_len = (SQLSMALLINT)connection_string.length();
     SQLSMALLINT conn_str_out_len = 0;
     SQLCHAR conn_str_out[MAX_CONN_STR_OUT + 1] = {0};
 
     auto sql_return = SQLDriverConnect(
-        handle_conn, NULL, (SQLCHAR *)dsn.c_str(), conn_str_in_len,
-        conn_str_out, (SQLSMALLINT)MAX_CONN_STR_OUT, &conn_str_out_len,
-        SQL_DRIVER_NOPROMPT);
+        handle_conn, NULL, (SQLCHAR *)connection_string.c_str(),
+        conn_str_in_len, conn_str_out, (SQLSMALLINT)MAX_CONN_STR_OUT,
+        &conn_str_out_len, SQL_DRIVER_NOPROMPT);
     if (sql_return == SQL_SUCCESS || sql_return == SQL_SUCCESS_WITH_INFO) {
       dialed = true;
     } else if (sql_return == SQL_NO_DATA_FOUND) {

src/include/odbc_scan.hpp

@@ -15,7 +15,7 @@
 
 namespace duckdb {
 struct OdbcScanBindData : public FunctionData {
-  string dsn;
+  string connection_string;
   string schema_name;
   string table_name;
   shared_ptr<OdbcEnvironment> environment;
@@ -289,7 +289,7 @@ class OdbcScanFunction : public TableFunction {
   OdbcScanBind(ClientContext &context, TableFunctionBindInput &input,
                vector<LogicalType> &return_types, vector<string> &names) {
     auto bind_data = make_uniq<OdbcScanBindData>();
-    bind_data->dsn = input.inputs[0].GetValue<string>();
+    bind_data->connection_string = input.inputs[0].GetValue<string>();
     bind_data->schema_name = input.inputs[1].GetValue<string>();
     bind_data->table_name = input.inputs[2].GetValue<string>();
 
@@ -298,7 +298,7 @@ class OdbcScanFunction : public TableFunction {
 
     bind_data->connection = make_shared<OdbcConnection>();
     bind_data->connection->Init(bind_data->environment);
-    bind_data->connection->Dial(bind_data->dsn);
+    bind_data->connection->Dial(bind_data->connection_string);
 
     bind_data->statement = make_uniq<OdbcStatement>(bind_data->connection);
     bind_data->statement->Init();
@@ -335,8 +335,7 @@ class OdbcScanFunction : public TableFunction {
   static unique_ptr<GlobalTableFunctionState>
   OdbcScanInitGlobalState(ClientContext &context,
                           TableFunctionInitInput &input) {
-    auto global_state = make_uniq<OdbcScanGlobalState>();
-    return global_state;
+    return make_uniq<OdbcScanGlobalState>();
   }
 
   static unique_ptr<LocalTableFunctionState>

templates/.odbc.ini.template

@@ -0,0 +1,2 @@
+[db2 odbctest]
+Driver = db2

templates/.odbcinst.ini.template

@@ -0,0 +1,2 @@
+[db2]
+Driver = ${DB2_DRIVER_PATH}