diff --git a/+dj/Relvar.m b/+dj/Relvar.m
index 802845ba..44ecda84 100755
--- a/+dj/Relvar.m
+++ b/+dj/Relvar.m
@@ -352,14 +352,25 @@ function update(self, attrname, value)
             
             switch true
                 case isNull
+                    assert(header.attributes(ix).isnullable, ...
+                            'attribute `%s` is not nullable.', attrname)
                     valueStr = 'NULL';
                     value = {};
                 case header.attributes(ix).isString
                     assert(dj.lib.isString(value), 'Value must be a string')
-                    valueStr = '"{S}"';
-                    value = {char(value)};
+                    if isempty(value)
+                        assert(header.attributes(ix).isnullable, ...
+                            'attribute `%s` is not nullable.', attrname)
+                        valueStr = 'NULL';
+                        value = {};
+                    else
+                        valueStr = '"{S}"';
+                        value = {char(value)};
+                    end
                 case header.attributes(ix).isBlob
                     if isempty(value) && header.attributes(ix).isnullable
+                        assert(header.attributes(ix).isnullable, ...
+                            'attribute `%s` is not nullable.', attrname)
                         valueStr = 'NULL';
                         value = {};
                     else
diff --git a/+tests/+lib/compareVersions.m b/+tests/+lib/compareVersions.m
new file mode 100644
index 00000000..46d7b27d
--- /dev/null
+++ b/+tests/+lib/compareVersions.m
@@ -0,0 +1,100 @@
+function res = compareVersions(verArray, verComp)
+    % compareVersions - Semantic version comparison (greater than or equal)
+    %
+    % This function evaluates if an array of semantic versions is greater than 
+    % or equal to a reference version.
+    %
+    % DISTRIBUTION:
+    %  GitHub:       https://github.com/guzman-raphael/compareVersions
+    %  FileExchange: https://www.mathworks.com/matlabcentral/fileexchange/71849-compareversions
+    %
+    % res = compareVersions(verArray, verComp)
+    % INPUT:
+    %   verArray: Cell array with the following conditions:
+    %              - be of length >= 1,
+    %              - contain only string elements, and
+    %              - each element must be of length >= 1.
+    %   verComp:  String or Char array that verArray will compare against for
+    %             greater than evaluation. Must be:
+    %              - be of length >= 1, and
+    %              - a string.
+    % OUTPUT:
+    %   res:      Logical array that identifies if each cell element in verArray
+    %             is greater than or equal to verComp.
+    % TESTS:
+    %   Tests included for reference. From root package directory,
+    %   use command: runtests
+    %
+    % EXAMPLES:
+    %   output = compareVersions({'3.2.4beta','9.5.2.1','8.0'}, '8.0.0'); %logical([0 1 1]) 
+    %
+    % NOTES:
+    %   Tests included for reference. From root package directory,
+    %   use command: runtests
+    %
+    % Tested: Matlab 9.5.0.944444 (R2018b) Linux
+    % Author: Raphael Guzman, DataJoint
+    %
+    % $License: MIT (use/copy/change/redistribute on own risk) $
+    % $File: compareVersions.m $
+    % History:
+    % 001: 2019-06-12 11:00, First version.
+    %
+    % OPEN BUGS:
+    %  - None 
+    res_n = length(verArray);
+    if ~res_n || max(cellfun(@(c) ~ischar(c) && ...
+            ~isstring(c),verArray)) > 0 || min(cellfun('length',verArray)) == 0
+        msg = {
+            'compareVersions:Error:CellArray'
+            'Cell array to verify must:'
+            '- be of length >= 1,'
+            '- contain only string elements, and'
+            '- each element must be of length >= 1.'
+        };
+        error('compareVersions:Error:CellArray', sprintf('%s\n',msg{:}));
+    end
+    if ~ischar(verComp) && ~isstring(verComp) || length(verComp) == 0
+        msg = {
+            'compareVersions:Error:VersionRef'
+            'Version reference must:'
+            '- be of length >= 1, and'
+            '- a string.'
+        };
+        error('compareVersions:Error:VersionRef', sprintf('%s\n',msg{:}));
+    end
+    res = false(1, res_n);
+    for i = 1:res_n
+        shortVer = strsplit(verArray{i}, '.');
+        shortVer = cellfun(@(x) str2double(regexp(x,'\d*','Match')), shortVer(1,:));
+        longVer = strsplit(verComp, '.');
+        longVer = cellfun(@(x) str2double(regexp(x,'\d*','Match')), longVer(1,:)); 
+        shortVer_p = true;
+        longVer_p = false;
+        shortVer_s = length(shortVer);
+        longVer_s = length(longVer);
+
+        if shortVer_s > longVer_s
+            [longVer shortVer] = deal(shortVer,longVer);
+            [longVer_s shortVer_s] = deal(shortVer_s,longVer_s);
+            [longVer_p shortVer_p] = deal(shortVer_p,longVer_p);
+        end
+
+        shortVer = [shortVer zeros(1,longVer_s - shortVer_s)];
+        diff = shortVer - longVer;
+        match = diff ~= 0;
+       
+        if ~match
+            res(i) = true;
+        else
+            pos = 1:longVer_s;
+            pos = pos(match);
+            val = diff(pos(1));
+            if val > 0
+                res(i) = shortVer_p;
+            elseif val < 0
+                res(i) = longVer_p;
+            end
+        end
+    end
+end
\ No newline at end of file
diff --git a/+tests/Main.m b/+tests/Main.m
index e7986e8e..4f14f0a7 100644
--- a/+tests/Main.m
+++ b/+tests/Main.m
@@ -1,102 +1,5 @@
 classdef Main < ...
     tests.TestConnection & ...
+    tests.TestRelationalOperand & ...
     tests.TestTls
-
-    properties (Constant)
-        CONN_INFO_ROOT = struct(...
-            'host', getenv('DJ_HOST'), ...
-            'user', getenv('DJ_USER'), ...
-            'password', getenv('DJ_PASS'));
-        CONN_INFO = struct(...
-            'host', getenv('DJ_TEST_HOST'), ...
-            'user', getenv('DJ_TEST_USER'), ...
-            'password', getenv('DJ_TEST_PASSWORD'));
-    end
-
-    methods (TestClassSetup)
-        function init(testCase)
-            disp('---------------INIT---------------');
-            clear functions;
-            testCase.addTeardown(@testCase.dispose);
-            
-            curr_conn = dj.conn(testCase.CONN_INFO_ROOT.host, ...
-                testCase.CONN_INFO_ROOT.user, testCase.CONN_INFO_ROOT.password,'',true);
-
-            ver = curr_conn.query('select @@version as version').version;
-            if dj.lib.compareVersions(ver,'5.8')
-                cmd = {...
-                'CREATE USER IF NOT EXISTS ''datajoint''@''%%'' '
-                'IDENTIFIED BY ''datajoint'';'
-                };
-                curr_conn.query(sprintf('%s',cmd{:}));
-
-                cmd = {...
-                'GRANT ALL PRIVILEGES ON `djtest%%`.* TO ''datajoint''@''%%'';'
-                };
-                curr_conn.query(sprintf('%s',cmd{:}));
-
-                cmd = {...
-                'CREATE USER IF NOT EXISTS ''djview''@''%%'' '
-                'IDENTIFIED BY ''djview'';'
-                };
-                curr_conn.query(sprintf('%s',cmd{:}));
-
-                cmd = {...
-                'GRANT SELECT ON `djtest%%`.* TO ''djview''@''%%'';'
-                };
-                curr_conn.query(sprintf('%s',cmd{:}));
-
-                cmd = {...
-                'CREATE USER IF NOT EXISTS ''djssl''@''%%'' '
-                'IDENTIFIED BY ''djssl'' '
-                'REQUIRE SSL;'
-                };
-                curr_conn.query(sprintf('%s',cmd{:}));
-
-                cmd = {...
-                'GRANT SELECT ON `djtest%%`.* TO ''djssl''@''%%'';'
-                };
-                curr_conn.query(sprintf('%s',cmd{:}));
-            else
-                cmd = {...
-                'GRANT ALL PRIVILEGES ON `djtest%%`.* TO ''datajoint''@''%%'' '
-                'IDENTIFIED BY ''datajoint'';'
-                };
-                curr_conn.query(sprintf('%s',cmd{:}));
-
-                cmd = {...
-                'GRANT SELECT ON `djtest%%`.* TO ''djview''@''%%'' '
-                'IDENTIFIED BY ''djview'';'
-                };
-                curr_conn.query(sprintf('%s',cmd{:}));
-
-                cmd = {...
-                'GRANT SELECT ON `djtest%%`.* TO ''djssl''@''%%'' '
-                'IDENTIFIED BY ''djssl'' '
-                'REQUIRE SSL;'
-                };
-                curr_conn.query(sprintf('%s',cmd{:}));
-            end
-        end
-    end
-       
-    methods (Static)
-        function dispose()
-            disp('---------------DISP---------------');
-            warning('off','MATLAB:RMDIR:RemovedFromPath');
-            
-            curr_conn = dj.conn(tests.Main.CONN_INFO_ROOT.host, ...
-                tests.Main.CONN_INFO_ROOT.user, tests.Main.CONN_INFO_ROOT.password, '',true);
-
-            cmd = {...
-            'DROP USER ''datajoint''@''%%'';'
-            'DROP USER ''djview''@''%%'';'
-            'DROP USER ''djssl''@''%%'';'
-            };
-            res = curr_conn.query(sprintf('%s',cmd{:}));
-            curr_conn.delete;
-
-            warning('on','MATLAB:RMDIR:RemovedFromPath');
-        end
-    end
-end
+end
\ No newline at end of file
diff --git a/+tests/Prep.m b/+tests/Prep.m
new file mode 100644
index 00000000..47395249
--- /dev/null
+++ b/+tests/Prep.m
@@ -0,0 +1,135 @@
+classdef Prep < matlab.unittest.TestCase
+    % Setup and teardown for tests.
+    properties (Constant)
+        CONN_INFO_ROOT = struct(...
+            'host', getenv('DJ_HOST'), ...
+            'user', getenv('DJ_USER'), ...
+            'password', getenv('DJ_PASS'));
+        CONN_INFO = struct(...
+            'host', getenv('DJ_TEST_HOST'), ...
+            'user', getenv('DJ_TEST_USER'), ...
+            'password', getenv('DJ_TEST_PASSWORD'));
+        S3_CONN_INFO = struct(...
+            'endpoint', getenv('S3_ENDPOINT'), ...
+            'access_key', getenv('S3_ACCESS_KEY'), ...
+            'secret_key', getenv('S3_SECRET_KEY'), ...
+            'bucket', getenv('S3_BUCKET'));
+        PREFIX = 'djtest';
+    end
+    properties
+        test_root;
+    end
+    methods
+        function obj = Prep()
+            % Initialize test_root
+            test_pkg_details = what('tests');
+            [test_root, ~, ~] = fileparts(test_pkg_details.path);
+            obj.test_root = [test_root '/+tests'];
+        end
+     end
+    methods (TestClassSetup)
+        function init(testCase)
+            disp('---------------INIT---------------');
+            clear functions;
+            addpath([testCase.test_root '/test_schemas']);
+
+            curr_conn = dj.conn(testCase.CONN_INFO_ROOT.host, ...
+                testCase.CONN_INFO_ROOT.user, testCase.CONN_INFO_ROOT.password,'',true);
+            % create test users
+            ver = curr_conn.query('select @@version as version').version;
+            if tests.lib.compareVersions(ver,'5.8')
+                cmd = {...
+                'CREATE USER IF NOT EXISTS ''datajoint''@''%%'' '
+                'IDENTIFIED BY ''datajoint'';'
+                };
+                curr_conn.query(sprintf('%s',cmd{:}));
+
+                cmd = {...
+                'GRANT ALL PRIVILEGES ON `djtest%%`.* TO ''datajoint''@''%%'';'
+                };
+                curr_conn.query(sprintf('%s',cmd{:}));
+
+                cmd = {...
+                'CREATE USER IF NOT EXISTS ''djview''@''%%'' '
+                'IDENTIFIED BY ''djview'';'
+                };
+                curr_conn.query(sprintf('%s',cmd{:}));
+
+                cmd = {...
+                'GRANT SELECT ON `djtest%%`.* TO ''djview''@''%%'';'
+                };
+                curr_conn.query(sprintf('%s',cmd{:}));
+
+                cmd = {...
+                'CREATE USER IF NOT EXISTS ''djssl''@''%%'' '
+                'IDENTIFIED BY ''djssl'' '
+                'REQUIRE SSL;'
+                };
+                curr_conn.query(sprintf('%s',cmd{:}));
+
+                cmd = {...
+                'GRANT SELECT ON `djtest%%`.* TO ''djssl''@''%%'';'
+                };
+                curr_conn.query(sprintf('%s',cmd{:}));
+            else
+                cmd = {...
+                'GRANT ALL PRIVILEGES ON `djtest%%`.* TO ''datajoint''@''%%'' '
+                'IDENTIFIED BY ''datajoint'';'
+                };
+                curr_conn.query(sprintf('%s',cmd{:}));
+
+                cmd = {...
+                'GRANT SELECT ON `djtest%%`.* TO ''djview''@''%%'' '
+                'IDENTIFIED BY ''djview'';'
+                };
+                curr_conn.query(sprintf('%s',cmd{:}));
+
+                cmd = {...
+                'GRANT SELECT ON `djtest%%`.* TO ''djssl''@''%%'' '
+                'IDENTIFIED BY ''djssl'' '
+                'REQUIRE SSL;'
+                };
+                curr_conn.query(sprintf('%s',cmd{:}));
+            end
+        end
+    end
+    methods (TestClassTeardown)
+        function dispose(testCase)
+            disp('---------------DISP---------------');
+            warning('off','MATLAB:RMDIR:RemovedFromPath');
+
+            curr_conn = dj.conn(testCase.CONN_INFO_ROOT.host, ...
+                testCase.CONN_INFO_ROOT.user, testCase.CONN_INFO_ROOT.password, '',true);
+
+            % remove databases
+            curr_conn.query('SET FOREIGN_KEY_CHECKS=0;');
+            res = curr_conn.query(['SHOW DATABASES LIKE "' testCase.PREFIX '_%";']);
+            for i = 1:length(res.(['Database (' testCase.PREFIX '_%)']))
+                curr_conn.query(['DROP DATABASE ' ...
+                    res.(['Database (' testCase.PREFIX '_%)']){i} ';']);
+            end
+            curr_conn.query('SET FOREIGN_KEY_CHECKS=1;');
+
+            % remove users
+            cmd = {...
+            'DROP USER ''datajoint''@''%%'';'
+            'DROP USER ''djview''@''%%'';'
+            'DROP USER ''djssl''@''%%'';'
+            };
+            res = curr_conn.query(sprintf('%s',cmd{:}));
+            curr_conn.delete;
+
+            % Remove getSchemas to ensure they are created by tests.
+            files = dir([testCase.test_root '/test_schemas']);
+            dirFlags = [files.isdir] & ~strcmp({files.name},'.') & ~strcmp({files.name},'..');
+            subFolders = files(dirFlags);
+            for k = 1 : length(subFolders)
+                delete([testCase.test_root '/test_schemas/' subFolders(k).name ...
+                    '/getSchema.m']);
+                % delete(['test_schemas/+University/getSchema.m'])
+            end
+            rmpath([testCase.test_root '/test_schemas']);
+            warning('on','MATLAB:RMDIR:RemovedFromPath');
+        end
+    end
+end
\ No newline at end of file
diff --git a/+tests/TestConnection.m b/+tests/TestConnection.m
index d57d901b..92b113a3 100644
--- a/+tests/TestConnection.m
+++ b/+tests/TestConnection.m
@@ -1,7 +1,7 @@
-classdef TestConnection < matlab.unittest.TestCase
+classdef TestConnection < tests.Prep
     % TestConnection tests typical connection scenarios.
     methods (Test)
-        function testConnection(testCase)
+        function TestConnection_testConnection(testCase)
             st = dbstack;
             disp(['---------------' st(1).name '---------------']);
             testCase.verifyTrue(dj.conn(...
@@ -9,26 +9,35 @@ function testConnection(testCase)
                 testCase.CONN_INFO.user,...
                 testCase.CONN_INFO.password,'',true).isConnected);
         end
-        function testConnectionExists(testCase)
+        function TestConnection_testConnectionExists(testCase)
             % testConnectionExists tests that will not fail if connection open
             % to the same host.
             % Fix https://github.com/datajoint/datajoint-matlab/issues/160
             st = dbstack;
             disp(['---------------' st(1).name '---------------']);
-            dj.conn(testCase.CONN_INFO.host, '', '', '', '', true)
-            dj.conn(testCase.CONN_INFO.host, '', '', '', '', true)
+            dj.conn(testCase.CONN_INFO.host, '', '', '', '', true);
+            dj.conn(testCase.CONN_INFO.host, '', '', '', '', true);
         end
-        function testConnectionDiffHost(testCase)
+        function TestConnection_testConnectionDiffHost(testCase)
             % testConnectionDiffHost tests that will fail if connection open
             % to a different host.
             % Fix https://github.com/datajoint/datajoint-matlab/issues/160
             st = dbstack;
             disp(['---------------' st(1).name '---------------']);
-            dj.conn(testCase.CONN_INFO.host, '', '', '', '', true)
+            dj.conn(testCase.CONN_INFO.host, '', '', '', '', true);
             
             testCase.verifyError(@() dj.conn(...
                 'anything', '', '', '', '', true), ...
                 'DataJoint:Connection:AlreadyInstantiated');
         end
+        function TestConnection_testPort(testCase)
+            st = dbstack;
+            disp(['---------------' st(1).name '---------------']);
+            testCase.verifyError(@() dj.conn(...
+                [testCase.CONN_INFO.host ':3307'], ...
+                testCase.CONN_INFO.user,...
+                testCase.CONN_INFO.password,'',true), ...
+                'MySQL:Error');
+        end
     end
 end
\ No newline at end of file
diff --git a/+tests/TestRelationalOperand.m b/+tests/TestRelationalOperand.m
new file mode 100644
index 00000000..caf31207
--- /dev/null
+++ b/+tests/TestRelationalOperand.m
@@ -0,0 +1,36 @@
+classdef TestRelationalOperand < tests.Prep
+    % TestRelationalOperand tests relational operations.
+    methods (Test)
+        function TestRelationalOperand_testUpdateDate(testCase)
+            st = dbstack;
+            disp(['---------------' st(1).name '---------------']);
+            % https://github.com/datajoint/datajoint-matlab/issues/211
+            package = 'University';
+
+            c1 = dj.conn(...
+                testCase.CONN_INFO.host,... 
+                testCase.CONN_INFO.user,...
+                testCase.CONN_INFO.password,'',true);
+
+            dj.createSchema(package,[testCase.test_root '/test_schemas'], ...
+                [testCase.PREFIX '_university']);
+
+            insert(University.All, struct( ...
+                'id', 2, ...
+                'date', '2019-12-20' ...
+            ));
+            q = University.All & 'id=2';
+
+            new_value = '';
+            q.update('date', new_value);
+            testCase.verifyEqual(q.fetch1('date'),  new_value);
+
+            new_value = '2020-04-14';
+            q.update('date', new_value);
+            testCase.verifyEqual(q.fetch1('date'),  new_value);
+
+            q.update('date');
+            testCase.verifyEqual(q.fetch1('date'),  '');
+        end
+    end
+end
\ No newline at end of file
diff --git a/+tests/TestTls.m b/+tests/TestTls.m
index 9da70f8a..a340afb6 100644
--- a/+tests/TestTls.m
+++ b/+tests/TestTls.m
@@ -1,7 +1,7 @@
-classdef TestTls < matlab.unittest.TestCase
+classdef TestTls < tests.Prep
     % TestTls tests TLS connection scenarios.
     methods (Test)
-        function testSecureConn(testCase)
+        function TestTls_testSecureConn(testCase)
             % secure connection test
             st = dbstack;
             disp(['---------------' st(1).name '---------------']);
@@ -12,7 +12,7 @@ function testSecureConn(testCase)
                 '',true,true).query(...
                 'SHOW STATUS LIKE ''Ssl_cipher''').Value{1}) > 0);
         end
-        function testInsecureConn(testCase)
+        function TestTls_testInsecureConn(testCase)
             % insecure connection test
             st = dbstack;
             disp(['---------------' st(1).name '---------------']);
@@ -24,7 +24,7 @@ function testInsecureConn(testCase)
                 'SHOW STATUS LIKE ''Ssl_cipher''').Value{1}, ...
                 '');
         end
-        function testPreferredConn(testCase)
+        function TestTls_testPreferredConn(testCase)
             % preferred connection test
             st = dbstack;
             disp(['---------------' st(1).name '---------------']);
@@ -35,7 +35,7 @@ function testPreferredConn(testCase)
                 '',true).query(...
                 'SHOW STATUS LIKE ''Ssl_cipher''').Value{1}) > 0);
         end
-        function testRejectException(testCase)
+        function TestTls_testRejectException(testCase)
             % test exception on require TLS
             st = dbstack;
             disp(['---------------' st(1).name '---------------']);
@@ -54,7 +54,7 @@ function testRejectException(testCase)
                     ["requires secure connection","Access denied"])); %MySQL8,MySQL5
             end
         end
-        function testStructException(testCase)
+        function TestTls_testStructException(testCase)
             % test exception on TLS struct
             st = dbstack;
             disp(['---------------' st(1).name '---------------']);
@@ -63,7 +63,7 @@ function testStructException(testCase)
                 testCase.CONN_INFO.user, ...
                 testCase.CONN_INFO.password, ...
                 '',true,struct('ca','fake/path/some/where')), ...
-                'DataJoint:TLS:InvalidStruct');
+                'mYm:TLS:InvalidStruct');
         end
     end
 end
\ No newline at end of file
diff --git a/+tests/test_schemas/+University/All.m b/+tests/test_schemas/+University/All.m
new file mode 100644
index 00000000..55d4be71
--- /dev/null
+++ b/+tests/test_schemas/+University/All.m
@@ -0,0 +1,12 @@
+%{
+# All
+id      : int   
+---
+string=null   : varchar(30)
+datetime=null : datetime
+date=null     : date
+number=null   : float
+blob=null     : longblob
+%}
+classdef All < dj.Manual
+end
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index 3a9626a7..c9a8c43f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,10 @@
 mym/
 *.mltbx
 *.env
+notebook
+*getSchema.m
+docker-compose.yml
+.vscode
+matlab.prf
+win.*
+macos.*
\ No newline at end of file