Class EntitySchemaCoalesceQueryFunction

Function that returns the first expression that is other than null from the list of arguments.

Inheritance
System.Object
MetaItem
EntitySchemaQueryFunction
EntitySchemaCoalesceQueryFunction
Implements
System.ICloneable
Inherited Members
System.Object.ToString()
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.ReferenceEquals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
Namespace: Terrasoft.Core.Entities
Assembly: Terrasoft.Core.dll
Syntax
public class EntitySchemaCoalesceQueryFunction : EntitySchemaQueryFunction, IMetaItem, IMetaDataSerializable, ICloneable

Constructors

EntitySchemaCoalesceQueryFunction(EntitySchemaCoalesceQueryFunction)

Initializes the EntitySchemaCoalesceQueryFunction instance that is a clone of the passed-in function.

Declaration
public EntitySchemaCoalesceQueryFunction(EntitySchemaCoalesceQueryFunction source)
Parameters
Type Name Description
EntitySchemaCoalesceQueryFunction source

The instance of the EntitySchemaCoalesceQueryFunction function whose clone is being created.

EntitySchemaCoalesceQueryFunction(EntitySchemaQuery)

Initializes the EntitySchemaCoalesceQueryFunction instance for the specified entity schema query.

Declaration
public EntitySchemaCoalesceQueryFunction(EntitySchemaQuery parentQuery)
Parameters
Type Name Description
EntitySchemaQuery parentQuery

Query against the schema of the entity that contains the function.

Properties

Expressions

Collection of expressions of function arguments.

Declaration
public EntitySchemaQueryExpressionCollection Expressions { get; }
Property Value
Type Description
EntitySchemaQueryExpressionCollection

HasExpressions

Indicates whether at least one item exists in the collection of expressions of the function arguments.

Declaration
public bool HasExpressions { get; }
Property Value
Type Description
System.Boolean

QueryAlias

The alias of the function in the SQL query.

Declaration
public override string QueryAlias { get; }
Property Value
Type Description
System.String
Overrides

Methods

ApplyMetaDataValue(DataReader)

Declaration
protected override void ApplyMetaDataValue(DataReader reader)
Parameters
Type Name Description
DataReader reader
Overrides

Clone()

Creates the clone of the current EntitySchemaCoalesceQueryFunction instance.

Declaration
public override object Clone()
Returns
Type Description
System.Object

The System.Object instance that is a clone of the current function instance.
Overrides

CreateQueryColumnExpression(DBSecurityEngine)

For the current function, gets the query column expression that is generated taking into account the specified access rights.

Declaration
public override QueryColumnExpression CreateQueryColumnExpression(DBSecurityEngine dbSecurityEngine)
Parameters
Type Name Description
DBSecurityEngine dbSecurityEngine

The DBSecurityEngine instance that determines the access rights.
Returns
Type Description
QueryColumnExpression

The QueryColumnExpression instance for the current function, which is generated taking into account the dbSecurityEngine access rights.
Overrides
Exceptions
Type Condition
ArgumentEmptyException

If null is passed as the dbSecurityEngine parameter.
InvalidObjectStateException

If the collection of expressions of the function arguments does not have any items or is null.

GetArguments()

Gets the collection of expressions of function arguments.

Declaration
public override EntitySchemaQueryExpressionCollection GetArguments()
Returns
Type Description
EntitySchemaQueryExpressionCollection

Collection of expressions of function arguments.
Overrides

GetCaption()

Gets the caption of the expression function.

Declaration
public override string GetCaption()
Returns
Type Description
System.String

String of the function caption.
Overrides

GetIsSupportedDataValueType(DataValueType)

Indicates whether the output of the function has the specified data type.

Declaration
public override bool GetIsSupportedDataValueType(DataValueType dataValueType)
Parameters
Type Name Description
DataValueType dataValueType

Data type.
Returns
Type Description
System.Boolean

Always gets true.
Overrides

GetResultDataValueType(DataValueTypeManager)

Gets the data type of the output returned by the function, using the specified data type manager.

Declaration
public override DataValueType GetResultDataValueType(DataValueTypeManager dataValueTypeManager)
Parameters
Type Name Description
DataValueTypeManager dataValueTypeManager

Data type manager.
Returns
Type Description
DataValueType

Data type of the output returned by the function.
Overrides
Exceptions
Type Condition
InvalidObjectStateException

If the collection of expressions of the function arguments does not have any items or is null.

SpecifyQueryAlias(String)

For the current expression function, defines the specified alias in the resulting SQL query.

Declaration
public void SpecifyQueryAlias(string queryAlias)
Parameters
Type Name Description
System.String queryAlias

Alias to define for the current function.

WriteMetaData(DataWriter)

Serializes the expression function, using the passed-in DataWriter instance.

Declaration
public override void WriteMetaData(DataWriter writer)
Parameters
Type Name Description
DataWriter writer

The DataWriter instance used for serializing the expression function.
Overrides

Implements

System.ICloneable

Extension Methods