Interface IProjectionQuery<T>

Represent result of projection operation.

Inherited Members
Namespace: Kros.KORM.Query
Assembly: Kros.KORM.dll
Syntax
public interface IProjectionQuery<T> : IQueryBase<T>, IOrderedQueryable<T>, IQueryable<T>, IEnumerable<T>, IOrderedQueryable, IQueryable, IEnumerable
Type Parameters
Name Description
T

Type of model class.

Methods

Any(RawSqlString, Object[])

Check if exist elements in the table which match condition.

Declaration
bool Any(RawSqlString whereCondition, params object[] args)
Parameters
Type Name Description
RawSqlString whereCondition

The where condition.
System.Object[] args

The arguments for where.
Returns
Type Description
System.Boolean

true if exist elements in the table which match condition; otherwise, false.
Examples
                var exist = database.Query<Person>().Any("Age > @1", 18);
Exceptions
Type Condition
System.ArgumentNullException

if whereCondition is null or white string.

Any(FormattableString)

Check if exist elements in the table which match condition.

Declaration
bool Any(FormattableString whereCondition)
Parameters
Type Name Description
System.FormattableString whereCondition

The where condition.
Returns
Type Description
System.Boolean

true if exist elements in the table which match condition; otherwise, false.
Examples
var exist = database.Query<Person>().Any($"Age > {18}");
Exceptions
Type Condition
System.ArgumentNullException

if whereCondition is null or white string.

FirstOrDefault(RawSqlString, Object[])

Returns the first item of which match where condition, or a default value if item doesn't exist.

Declaration
T FirstOrDefault(RawSqlString whereCondition, params object[] args)
Parameters
Type Name Description
RawSqlString whereCondition

The where condition.
System.Object[] args

The arguments for where.
Returns
Type Description
T

null if item doesn't exist; otherwise, the first item which match the condition.
Examples
var item = query.FirstOrDefault("Id = @1", 22);
Exceptions
Type Condition
System.ArgumentNullException

if whereCondition is null or white string.

FirstOrDefault(FormattableString)

Returns the first item of which match where condition, or a default value if item doesn't exist.

Declaration
T FirstOrDefault(FormattableString whereCondition)
Parameters
Type Name Description
System.FormattableString whereCondition

The where condition.
Returns
Type Description
T

null if item doesn't exist; otherwise, the first item which match the condition.
Examples
var item = query.FirstOrDefault($"Id = {22}");
Exceptions
Type Condition
System.ArgumentNullException

if whereCondition is null or white string.

GroupBy(String)

Add group by statement to sql query.

Declaration
IGroupedQuery<T> GroupBy(string groupBy)
Parameters
Type Name Description
System.String groupBy

The group by statement.
Returns
Type Description
IGroupedQuery<T>

Query for enumerable models.
Remarks

You can also add HAVING statement.

Examples
                var people = database.Query<Person>().GroupBy("FirstName, LastName");
Exceptions
Type Condition
System.ArgumentNullException

if groupBy is null or white string.

OrderBy(String)

Add order by statement to sql.

Declaration
IOrderedQuery<T> OrderBy(string orderBy)
Parameters
Type Name Description
System.String orderBy

The order by statement.
Returns
Type Description
IOrderedQuery<T>

Query for enumerable models.
Examples
                var people = database.Query<Person>().OrderBy("FirstName DESC, LastName");
Exceptions
Type Condition
System.ArgumentNullException

if orderBy is null or white string.

Where(RawSqlString, Object[])

Add where condition to sql.

Declaration
IFilteredQuery<T> Where(RawSqlString whereCondition, params object[] args)
Parameters
Type Name Description
RawSqlString whereCondition

The where condition.
System.Object[] args

The arguments for where.
Returns
Type Description
IFilteredQuery<T>

Query for enumerable models.
Examples
                var people = database.Query<Person>().Where("Id < @1 AND Age > @2", 1000, 18);
Exceptions
Type Condition
System.ArgumentNullException

if whereCondition is null or white string.

Where(FormattableString)

Add where condition to sql.

Declaration
IFilteredQuery<T> Where(FormattableString whereCondition)
Parameters
Type Name Description
System.FormattableString whereCondition

The where condition.
Returns
Type Description
IFilteredQuery<T>

Query for enumerable models.
Examples
var item = query.Where($"Id = {1}")
Exceptions
Type Condition
System.ArgumentNullException

if whereCondition is null or white string.

See Also