Class ColumnDescriptor

Stores mapping entity column descriptor.

Inheritance

object

ColumnDescriptor

Implements

IColumnChangeDescriptor

Namespace: LinqToDB.Mapping

Assembly: linq2db.dll

Syntax

public class ColumnDescriptor : IColumnChangeDescriptor

Constructors

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ColumnDescriptor(MappingSchema, EntityDescriptor, ColumnAttribute?, MemberAccessor, bool)

Creates descriptor instance.

Declaration

public ColumnDescriptor(MappingSchema mappingSchema, EntityDescriptor entityDescriptor, ColumnAttribute? columnAttribute, MemberAccessor memberAccessor, bool hasInheritanceMapping)

Parameters

Type	Name	Description
MappingSchema	mappingSchema	Mapping schema, associated with descriptor.
EntityDescriptor	entityDescriptor	Entity descriptor.
ColumnAttribute	columnAttribute	Column attribute, from which descriptor data should be extracted.
MemberAccessor	memberAccessor	Column mapping member accessor.
bool	hasInheritanceMapping	Owning entity included in inheritance mapping.

Properties

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CanBeNull

Gets whether a column can contain null values.

Declaration

public bool CanBeNull { get; }

Property Value

Type	Description
bool

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ColumnName

Gets the name of a column in database. If not specified, MemberName value will be used.

Declaration

public string ColumnName { get; }

Property Value

Type	Description
string

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CreateFormat

Custom template for column definition in create table SQL expression, generated using CreateTable<T>(IDataContext, string?, string?, string?, string?, string?, DefaultNullable, string?, TableOptions) methods. Template accepts following string parameters:

{0} - column name;
{1} - column type;
{2} - NULL specifier;
{3} - identity specification.

Declaration

public string? CreateFormat { get; }

Property Value

Type	Description
string

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DataType

Gets LINQ to DB type for column.

Declaration

public DataType DataType { get; }

Property Value

Type	Description
DataType

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DbType

Gets the name of the database column type.

Declaration

public string? DbType { get; }

Property Value

Type	Description
string

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EntityDescriptor

Gets Entity descriptor.

Declaration

public EntityDescriptor EntityDescriptor { get; }

Property Value

Type	Description
EntityDescriptor

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HasInheritanceMapping

Indicates that owning entity included in inheritance mapping.

Declaration

public bool HasInheritanceMapping { get; }

Property Value

Type	Description
bool

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HasValuesToSkipOnInsert

Gets whether the column has specific values that should be skipped on insert.

Declaration

public bool HasValuesToSkipOnInsert { get; }

Property Value

Type	Description
bool

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HasValuesToSkipOnUpdate

Gets whether the column has specific values that should be skipped on update.

Declaration

public bool HasValuesToSkipOnUpdate { get; }

Property Value

Type	Description
bool

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IsDiscriminator

Gets whether a column contains a discriminator value for a LINQ to DB inheritance hierarchy. InheritanceMappingAttribute for more details. Default value: false.

Declaration

public bool IsDiscriminator { get; }

Property Value

Type	Description
bool

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IsIdentity

Gets whether a column contains values that the database auto-generates.

Declaration

public bool IsIdentity { get; }

Property Value

Type	Description
bool

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IsPrimaryKey

Gets whether this member represents a column that is part or all of the primary key of the table. Also see PrimaryKeyAttribute.

Declaration

public bool IsPrimaryKey { get; }

Property Value

Type	Description
bool

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Length

Gets the length of the database column.

Declaration

public int? Length { get; }

Property Value

Type	Description
int?

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MappingSchema

Gets MappingSchema for current ColumnDescriptor.

Declaration

public MappingSchema MappingSchema { get; }

Property Value

Type	Description
MappingSchema

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MemberAccessor

Gets column mapping member accessor.

Declaration

public MemberAccessor MemberAccessor { get; }

Property Value

Type	Description
MemberAccessor

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MemberInfo

Gets column mapping member (field or property).

Declaration

public MemberInfo MemberInfo { get; }

Property Value

Type	Description
MemberInfo

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MemberName

Gets the name of mapped member. When applied to class or interface, should contain name of property of field.

If column is mapped to a property or field of composite object, MemberName should contain a path to that member using dot as separator.

public class Address
{
    public string City     { get; set; }
    public string Street   { get; set; }
    public int    Building { get; set; }
}

[Column("city", "Residence.Street")]
[Column("user_name", "Name")]
public class User
{
    public string Name;

    [Column("street", ".Street")]
    [Column("building_number", MemberName = ".Building")]
    public Address Residence { get; set; }
}

Declaration

public string MemberName { get; }

Property Value

Type	Description
string

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MemberType

Gets type of column mapping member (field or property).

Declaration

public Type MemberType { get; }

Property Value

Type	Description
Type

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Order

Sort order for column list. Positive values first, then unspecified (null), then negative values.

Declaration

public int? Order { get; }

Property Value

Type	Description
int?

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Precision

Gets the precision of the database column.

Declaration

public int? Precision { get; }

Property Value

Type	Description
int?

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PrimaryKeyOrder

Gets order of current column in composite primary key. Order is used for query generation to define in which order primary key columns must be mentioned in query from columns with smallest order value to greatest.

Declaration

public int PrimaryKeyOrder { get; }

Property Value

Type	Description
int

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Scale

Gets the Scale of the database column.

Declaration

public int? Scale { get; }

Property Value

Type	Description
int?

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SequenceName

Gets sequence name for specified column.

Declaration

public SequenceNameAttribute? SequenceName { get; }

Property Value

Type	Description
SequenceNameAttribute

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SkipModificationFlags

Gets flags for which operation values are skipped.

Declaration

public SkipModification SkipModificationFlags { get; }

Property Value

Type	Description
SkipModification

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SkipOnEntityFetch

Gets whether a column must be explicitly defined in a Select statement to be fetched. If true, a "SELECT *"-ish statement won't retrieve this column. Default value: false.

Declaration

public bool SkipOnEntityFetch { get; }

Property Value

Type	Description
bool

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SkipOnInsert

Gets whether a column is insertable. This flag will affect only insert operations with implicit columns specification like Insert<T>(IDataContext, T, string?, string?, string?, string?, TableOptions) method and will be ignored when user explicitly specifies value for this column.

Declaration

public bool SkipOnInsert { get; }

Property Value

Type	Description
bool

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SkipOnUpdate

Gets whether a column is updatable. This flag will affect only update operations with implicit columns specification like Update<T>(IDataContext, T, string?, string?, string?, string?, TableOptions) method and will be ignored when user explicitly specifies value for this column.

Declaration

public bool SkipOnUpdate { get; }

Property Value

Type	Description
bool

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Storage

Gets storage property or field to hold the value from a column. Could be usefull e.g. in combination of private storage field and getter-only mapping property.

Declaration

public string? Storage { get; }

Property Value

Type	Description
string

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StorageInfo

Gets value storage member (field or property).

Declaration

public MemberInfo StorageInfo { get; }

Property Value

Type	Description
MemberInfo

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StorageType

Gets type of column value storage member (field or property).

Declaration

public Type StorageType { get; }

Property Value

Type	Description
Type

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ValueConverter

Gets value converter for specific column.

Declaration

public IValueConverter? ValueConverter { get; }

Property Value

Type	Description
IValueConverter

Methods

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ApplyConversions(MappingSchema, Expression, DbDataType, IValueConverter?, bool)

Helper function for applying all needed conversions for converting value to database type.

Declaration

public static Expression ApplyConversions(MappingSchema mappingSchema, Expression getterExpr, DbDataType dbDataType, IValueConverter? valueConverter, bool includingEnum)

Parameters

Type	Name	Description
MappingSchema	mappingSchema	Mapping schema.
Expression	getterExpr	Expression which returns value which has to be converted.
DbDataType	dbDataType	Database type.
IValueConverter	valueConverter	Optional IValueConverter
bool	includingEnum	Provides default enum conversion.

Returns

Type	Description
Expression	Expression with applied conversions.

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ApplyConversions(Expression, DbDataType, bool)

Helper function for applying all needed conversions for converting value to database type.

Declaration

public Expression ApplyConversions(Expression getterExpr, DbDataType dbDataType, bool includingEnum)

Parameters

Type	Name	Description
Expression	getterExpr	Expression which returns value which has to be converted.
DbDataType	dbDataType	Database type.
bool	includingEnum	Provides default enum conversion.

Returns

Type	Description
Expression	Expression with applied conversions.

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CalculateDbDataType(MappingSchema, Type)

Declaration

public static DbDataType CalculateDbDataType(MappingSchema mappingSchema, Type systemType)

Parameters

Type	Name	Description
MappingSchema	mappingSchema
Type	systemType

Returns

Type	Description
DbDataType

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GetConvertedDbDataType()

Returns DbDataType for current column after conversions.

Declaration

public DbDataType GetConvertedDbDataType()

Returns

Type	Description
DbDataType

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GetDbDataType(bool)

Returns DbDataType for current column.

Declaration

public DbDataType GetDbDataType(bool completeDataType)

Parameters

Type	Name	Description
bool	completeDataType

Returns

Type	Description
DbDataType

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GetDbParamLambda()

Returns Lambda for extracting column value, converted to database type or DataParameter, from entity object.

Declaration

public LambdaExpression GetDbParamLambda()

Returns

Type	Description
LambdaExpression	Returns Lambda which extracts member value to database type or DataParameter.

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GetDbValueLambda()

Returns Lambda for extracting column value, converted to database type, from entity object.

Declaration

public LambdaExpression GetDbValueLambda()

Returns

Type	Description
LambdaExpression	Returns Lambda which extracts member value to database type.

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GetDefaultDbParamExpression()

Returns default column value, converted to database type or DataParameter.

Declaration

public Expression GetDefaultDbParamExpression()

Returns

Type	Description
Expression

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GetDefaultDbValueExpression()

Returns Lambda for extracting column value, converted to database type, from entity object.

Declaration

public Expression GetDefaultDbValueExpression()

Returns

Type	Description
Expression	Returns Lambda which extracts member value to database type.

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GetOriginalValueLambda()

Returns Lambda for extracting original column value from entity object.

Declaration

public LambdaExpression GetOriginalValueLambda()

Returns

Type	Description
LambdaExpression	Returns Lambda which extracts member value.

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GetProviderValue(object)

Extracts column value, converted to database type, from entity object.

Declaration

public virtual object? GetProviderValue(object obj)

Parameters

Type	Name	Description
object	obj	Entity object to extract column value from.

Returns

Type	Description
object	Returns column value, converted to database type.

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ShouldSkip(object, EntityDescriptor, SkipModification)

Checks if the passed object has values that should bes skipped based on the given flags.

Declaration

public virtual bool ShouldSkip(object obj, EntityDescriptor descriptor, SkipModification flags)

Parameters

Type	Name	Description
object	obj	The object containing the values for the operation.
EntityDescriptor	descriptor	EntityDescriptor of the current instance.
SkipModification	flags	The flags that specify which operation should be checked.

Returns

Type	Description
bool	`true` if object contains values that should be skipped.

Implements

IColumnChangeDescriptor

Extension Methods

Sql.IsDistinctFrom<T>(T, T)

Sql.IsNotDistinctFrom<T>(T, T)

Map.DeepCopy<T>(T)

SqlExtensions.In<T>(T, T, T, T)

SqlExtensions.In<T>(T, T, T)

SqlExtensions.In<T>(T, params T[])

SqlExtensions.In<T>(T, IEnumerable<T>)

SqlExtensions.In<T>(T, IQueryable<T>)

SqlExtensions.NotIn<T>(T, T, T, T)

SqlExtensions.NotIn<T>(T, T, T)

SqlExtensions.NotIn<T>(T, params T[])

SqlExtensions.NotIn<T>(T, IEnumerable<T>)

SqlExtensions.NotIn<T>(T, IQueryable<T>)