TDAWhere

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Overview

The TDAWhere class is used to dynamically build WHERE statements.

uDAInterfaces

TDAWhere = class;

Property	Type	Description
Changed	Boolean	Returns true if the WHERE clause has been changed. This property will not reset to false automatically, but code using the TDAWhere class may set it to false externally after reacting to changes, to keep track of whether the clause changes again. For example, the IDASQLCommand implementations will set this to false when preparing the command with the back-end database, and then use the Changed flag to determine if the command needs to be re-prepared at a later time.
Clause	String	Holds the text representation of the current WHERE clause.
ClientFields	Boolean	Indicates whether the field names used when adding condition to the WHERE clause are client side field names (ie field names as defined in the data table), or server side field names (ie field names from the back-end database). When set to true, markers will be stored in the where clause to notify the server side that field names need to be mapped over to the names in the physical database using the column mapping.
DefaultOperator	TDADefaultOperator	Specifies the default operator that should be used of two conditions are subsequently added to the clause without an explicit call to AddOperator.
Empty	Boolean	Returns true if the where clause is empty, i.e. does not contain any conditions.
OnChange	TNotifyEvent	Fires whenever the where clause has changed by adding new conditions to it.

Method	Description
AddCondition	Adds a new condition to the WHERE clause. If no Operator was added previously, the new condition will be connected to the existing clause (if any) using the DefaultOperator.
AddConditions	Adds a number of new conditions to the WHERE clause. If no Operator was added previously, the new condition will be connected to the existing clause (if any) using the DefaultOperator.
AddOperator	Adds a new operator to the WHERE clause, to connect the previous condition with the next one.
AddText	Adds a plain text SQL to the WHERE clause. If no Operator was added previously, the new condition will be connected to the existing clause (if any) using the DefaultOperator.
AddValueGroup	Adds an SQL "IN" condition to the WHERE clause. If no Operator was added previously, the new condition will be connected to the existing clause (if any) using the DefaultOperator.
Clear	Clears the WHERE clause and removes all previously added conditions.
CloseBracket	Adds a closing bracket (parenthesis) to the WHERE clause, to close a group of conditions previously started with OpenBracket.
OpenBracket	Adds an opening bracket (parenthesis) to the WHERE clause, to group the following conditions.