Generates a SQL-like checksum value for a given string, producing a consistent integer representation.
This method is designed to facilitate efficient database indexing and querying by converting string values
to integer checksums, which can improve performance due to better indexing on numeric values.
Namespace:
System.Text
Assembly:
Walter.Cypher (in Walter.Cypher.dll)
[CodeSampleAttribute]
public static int AsSqlChecksum(
this string value
)
Parameters
- value
- Type: String
The string value to generate a checksum for, intended for database indexing or other purposes requiring a persistent numeric representation.
Return Value
An integer checksum that consistently represents the input string.
Utilizing an integer checksum for database indexes, particularly when paired with the original string value,
can significantly enhance query performance. Indexes on integer values generally perform better than those on
string values due to their smaller size and the efficiency of integer comparisons. An effective use case is
indexing a table by a checksum column alongside the original string column. This approach allows for
high-performance lookups by checksum with the query pattern:
SELECT * FROM users WHERE user_checksum = @checksum AND email = @email;
Here, 'user_checksum' is the integer checksum column. This pattern benefits from the efficiency of integer index lookups
while ensuring accuracy through a final string comparison, which is only applied to a narrowed down dataset
(often just a single or a small number of records), mitigating the risk of checksum collisions.
This method's implementation ensures compatibility across different database platforms, as it does not rely
on platform-specific checksum calculations. All databases support integer and string data types, making
this approach universally applicable without the need for SQL platform compatibility considerations.
