updates readme with examples (#26)

README.md

@@ -8,6 +8,134 @@ You can get the NuGet package [here.](https://www.nuget.org/packages/MsSqlCdc)
 
 The MS-SQL change data capture library, simplifies using MS-SQL-CDC by providing a simplified API to interact with the SQL functions for MS-SQL-CDC. The API has intentionally been made very simplistic, because the use-cases of the consumers of the library can vary a lot.
 
+### Examples
+
+Usage examples can be found under the [example folder](https://github.com/DAXGRID/mssql-cdc/tree/master/examples).
+
+## API
+
+### GetIsBitSet
+
+Indicates whether a captured column has been updated by checking whether its ordinal position is set within a provided bitmask.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+var columnOrdinal = await Cdc.GetColumnOrdinal(connection, "dbo_Employee", "Salary");
+var isBitSet = await Cdc.IsBitSet(connection, columnOrdinal, "my_update_mask");
+```
+
+### Has column changed
+
+Identifies whether the specified update mask indicates that the specified colum has been updated in the associated change row.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+await Cdc.HasColumnChanged(connection, "dbo_Employee", "Salary", "my_update_mask");
+```
+
+### Get column ordinal
+
+Get the column ordinal of the specified column as it appears in the change table associated with the specified capture instance.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+var columnOrdinal = await Cdc.GetColumnOrdinal(connection, "dbo_Employee", "Salary");
+```
+
+### Map time to LSN
+
+Map the log sequence number (LSN) value from the start_lsn column in the cdc.lsn_time_mapping system table for the specified time.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+var lsn = await Cdc.MapTimeToLsn(connection, DateTime.UtcNow, RelationalOperator.LargestLessThan);
+```
+
+### Map LSN to time
+
+Map date and time value from the tran_end_time column in the cdc.lsn_time_mapping system table for the specified log sequence number (LSN). You can use this function to systematically map LSN ranges to date ranges in a change table.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+var time = await Cdc.MapLsnToTime(connection, 120000);
+```
+
+### Get min LSN
+
+Get the start_lsn column value for the specified capture instance from the cdc.change_tables system table. This value represents the low endpoint of the validity interval for the capture instance.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+var minLsn = await Cdc.GetMinLsn(connection, "dbo_Employee");
+```
+
+### Get max LSN
+
+Get the maximum log sequence number (LSN) from the start_lsn column in the cdc.lsn_time_mapping system table. You can use this function to return the high endpoint of the change data capture timeline for any capture instance.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+var maxLsn = await Cdc.GetMaxLsn(connection);
+```
+
+### Get previous LSN
+
+Get the previous log sequence number (LSN) in the sequence based upon the specified LSN.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+var previousLsn = await Cdc.GetPreviousLsn(connection, 120000);
+```
+
+### Get next LSN
+
+Get the next log sequence number (LSN) in the sequence based upon the specified LSN.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+var nextLsn = await Cdc.GetNextLsn(connection, 120000);
+```
+
+### Get net changes
+
+Get one net change row for each source row changed within the specified Log Sequence Numbers (LSN) range.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+var netChanges = await Cdc.GetNetChanges(connection, "dbo_Employee", 120000, 120020);
+```
+
+### Get all changes
+
+Get one row for each change applied to the source table within the specified log sequence number (LSN) range. If a source row had multiple changes during the interval, each change is represented in the returned result set.
+
+```c#
+var connectionString = GetConnectionString();
+var connection = new SqlConnection(connectionString);
+await connection.OpenAsync();
+var allChanges = await Cdc.GetAllChanges(connection, "dbo_Employee", 120000, 120020);
+```
+
 ## Setup CDC on MS-SQL Server
 
 First make sure that you've enabled the MS-SQL agent, otherwise changes won't be captured in the CDC tables.