Dapper custom TypeHandler and null value
Iam using dapper to access both MySQL and MSSQL from same interface.
The problem Iam facing is that I have custom SqlMapper.TypeHandler for Nullable. The TypeHandler mapper is used to map Guid to binary(16) in databases.
The problem is with inserting and updating.
When the guid is not null it works in both MySQL and MSSQL. But when the guid value is null it only works in MySQL.
The problem is I believe that MSSQL when inserting NULL needs a type of the column.
I did change some code in Dapper when custom TypeHandler.Parse is about to call and the value is null to ask the handler to prepare DbType to the DbParameter, so I set it to change the type always to DbType.Binary. And it worked! But only for inserting and not updating.
Because when dapper calles update it doesnt call LookupDbType for parameter type when the parameters value is null. And I dont know Dapper that good to be confident to do some more changes.
Basically when using custom SqlMapper.TypeHandler where T is nullable and actually is null when inserting or updating database, it doesnt work in MSSQL and throws "Implicit conversion from data type".
Anyone had the same problem? And solved it somehow easily?
Thank you.
c# mysql
sql-server dapper asked Nov 16 '18 at 15:23
TomCrowTomCrow
678
add a comment |
Iam using dapper to access both MySQL and MSSQL from same interface.
The problem Iam facing is that I have custom SqlMapper.TypeHandler for Nullable. The TypeHandler mapper is used to map Guid to binary(16) in databases.
The problem is with inserting and updating.
When the guid is not null it works in both MySQL and MSSQL. But when the guid value is null it only works in MySQL.
The problem is I believe that MSSQL when inserting NULL needs a type of the column.
I did change some code in Dapper when custom TypeHandler.Parse is about to call and the value is null to ask the handler to prepare DbType to the DbParameter, so I set it to change the type always to DbType.Binary. And it worked! But only for inserting and not updating.
Because when dapper calles update it doesnt call LookupDbType for parameter type when the parameters value is null. And I dont know Dapper that good to be confident to do some more changes.
Basically when using custom SqlMapper.TypeHandler where T is nullable and actually is null when inserting or updating database, it doesnt work in MSSQL and throws "Implicit conversion from data type".
Anyone had the same problem? And solved it somehow easily?
Thank you.
c# mysql
sql-server dapper asked Nov 16 '18 at 15:23
TomCrowTomCrow
678
add a comment |
Iam using dapper to access both MySQL and MSSQL from same interface.
The problem Iam facing is that I have custom SqlMapper.TypeHandler for Nullable. The TypeHandler mapper is used to map Guid to binary(16) in databases.
The problem is with inserting and updating.
When the guid is not null it works in both MySQL and MSSQL. But when the guid value is null it only works in MySQL.
The problem is I believe that MSSQL when inserting NULL needs a type of the column.
I did change some code in Dapper when custom TypeHandler.Parse is about to call and the value is null to ask the handler to prepare DbType to the DbParameter, so I set it to change the type always to DbType.Binary. And it worked! But only for inserting and not updating.
Because when dapper calles update it doesnt call LookupDbType for parameter type when the parameters value is null. And I dont know Dapper that good to be confident to do some more changes.
Basically when using custom SqlMapper.TypeHandler where T is nullable and actually is null when inserting or updating database, it doesnt work in MSSQL and throws "Implicit conversion from data type".
Anyone had the same problem? And solved it somehow easily?
Thank you.
c# mysql
sql-server dapper asked Nov 16 '18 at 15:23
TomCrowTomCrow
678
Iam using dapper to access both MySQL and MSSQL from same interface.
The problem Iam facing is that I have custom SqlMapper.TypeHandler for Nullable. The TypeHandler mapper is used to map Guid to binary(16) in databases.
The problem is with inserting and updating.
When the guid is not null it works in both MySQL and MSSQL. But when the guid value is null it only works in MySQL.
The problem is I believe that MSSQL when inserting NULL needs a type of the column.
I did change some code in Dapper when custom TypeHandler.Parse is about to call and the value is null to ask the handler to prepare DbType to the DbParameter, so I set it to change the type always to DbType.Binary. And it worked! But only for inserting and not updating.
Because when dapper calles update it doesnt call LookupDbType for parameter type when the parameters value is null. And I dont know Dapper that good to be confident to do some more changes.
Basically when using custom SqlMapper.TypeHandler where T is nullable and actually is null when inserting or updating database, it doesnt work in MSSQL and throws "Implicit conversion from data type".
Anyone had the same problem? And solved it somehow easily?
Thank you.
c# mysql
sql-server dapper c# mysql
sql-server dapper asked Nov 16 '18 at 15:23
TomCrowTomCrow
678
asked Nov 16 '18 at 15:23
TomCrowTomCrow
678
asked Nov 16 '18 at 15:23
TomCrowTomCrow
678
asked Nov 16 '18 at 15:23
TomCrowTomCrow
678
asked Nov 16 '18 at 15:23
TomCrowTomCrow
678
678
add a comment |
add a comment |
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