![]() Because in Mysql better to use Not operator for boolean data types. Source= StackTrace:Īt `1.NullableField(ObjectĪt (DataRow row, String columnName)Īt .b_1_0(DataRowĪt `2.MoveNext()Īt `1.ctor(IEnumerable`1 collection)Īt (IEnumerable`1 source)Īt (String userName) in WebService1.asmx. This query will give you faster and appropriate result. HResult=-2147467262 Message=Specified cast is not valid. System.InvalidCastException was unhandled by user code MySqlConnection cnMySQL = new MySqlConnection(connString) The database connection: string connString = "SERVER=localhost" + " " + If I replace it with `enabled = true` everything works. I got the same problem also when I use `enabled = "1".Equals(row.Field("enabled"))` and `enabled = row.Field("enabled")=1`. I think the error is the boolean data type of C#. I get the error at the enabled = row.Field("enabled") line. ![]() I get an error when trying to read the enabled variable:Īn exception of type 'System.InvalidCastException' occurred in In the database the enabled field is defined as: enabled boolean default false, The field enabled is declared as a boolean in the mysql database. Adding a boolean column with a default value. List accounts = dt.AsEnumerable().Select(row => Adding a column in MySQL involves using the ALTER TABLE command. ![]() I am using a data table: DataTable dt = new DataTable() If there is a column in it that contains a default value then whenever a new row will be inserted to this table and you have not assigned any value to the default value column then the default value will be automatically inserted for that row.I am trying to read a boolean ( enabled field) from the database, and use it to initialize objects. ![]() So as a general case I would suggest: where Subscription.paid 0 or Subscription. If you want to read more about creating tables in MySQL, click the below link.Ĭreate table with constraints MySQL query What is the meaning of adding default value to a column in MySQL?Īdding a default value to a column in MySQL means that if no value is specified for that column when a new record is inserted, the default value will be used.įor example, if you have a table named employee that has multiple columns in it. When you left join a table with a boolean field, the result set may contain a NULL value even though the joined tables schema does not permit it. In the above query, we have assigned a false value to the column is_active in the create table SQL query. To add a boolean type column with a default value while creating a table in MySQL, the following SQL syntax can be used:įor example, if we want to create a table named student in our MySQL database with a column named is_active then we can use the below MySQL query. Add boolean type column with default value while creating the table If you want to read more about ALTER TABLE query click here. Next, assign a default value 0(false) or 1(true) to the column and run the MySQL query.įinally, use the SELECT command to verify that the new column has been added and that the default value is correct. Add with default value false(0) ALTER TABLE userĪdd with default value true(1) ALTER TABLE userĪdding a Boolean column with a default value to an existing MySQL table can be done in a few simple steps.įirst, use the ALTER TABLE command to add the new column. ![]()
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