MySqlDependencyCheckType Enumeration

In This Topic

Determines which method MySqlDependency should use for checking tables for changes.

Syntax

Visual Basic
C#

'Declaration
 
Public Enum MySqlDependencyCheckType 
   Inherits System.Enum
   Implements System.IComparable, System.IConvertible, System.IFormattable

public enum MySqlDependencyCheckType : System.Enum, System.IComparable, System.IConvertible, System.IFormattable

Members

Member	Description
Checksum	Check using the CHECKSUM TABLE statement.
Default	Check using a TIMESTAMP column, if the table has such a column; otherwise, check using the CHECKSUM TABLE statement.
Timestamp	Check using a TIMESTAMP column. An exception is thrown if a table to check does not have such a column.

Remarks

When specifying the method to use, you need to take the following considerations into account:

The CHECKSUM TABLE statement is only efficient against MyISAM tables, created with the CHECKSUM=1 clause.
While using timestamp columns is more efficient, in most cases it requires increasing the group_concat_max_len value.
If a table contains hundreds of millions of rows, and you use timestamp columns for tracking changes, 32-bit MySQL won't allow setting group_concat_max_len to a high enough value to detect changes in any of the rows, and CHECKSUM TABLE statement would probably be too slow. In this case you may need to implement your own function to track changes.

Inheritance Hierarchy

System.Object
   System.ValueType
      System.Enum
         Devart.Data.MySql.MySqlDependencyCheckType

Reference

Devart.Data.MySql Namespace

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