net.as_development.asdk.api.db

Interface IDBQuery<TEntity extends IEntity>

All Known Implementing Classes:

DBQuery

public interface IDBQuery<TEntity extends IEntity>

Queries can be used to search for data base entities which match to a set of specified criteria. We do not provide a special language as e.g. SQL it does. We provide a more 'object oriented' approach. One example: You search for an entity where the attribute 'a' is equals to '1' and where another attribute 'b' match the wildcard value 'any_val%'. In normal SQL you would write these: "select * from my_table where a = 1 and b like 'any_val%'" Here you can write the same as: IDBQuery iQuery = ...; iQuery.setQueryPart (0, EQueryPartBinding.AND, EQueryPartOperation.MATCH, "a", 1 ); iQuery.setQueryPart (1, EQueryPartBinding.AND, EQueryPartOperation.LIKE , "b", "any_val*"); First line add an operation 'a = 1' to the internal query. The boolean operation AND will be ignored ... because there is no further leading operation on the left side .-) Second line add an operation 'and b like any_val%' to the internal query. Because it's not the leading operation the boolean operator AND will be used real here. Further the wildcard-asterix '*' will be translated to a value which is supported by the internal DB back end. First parameter of setQueryPart () will specify an index of that query part within the internal created query (string). So you can mix these two lines of code in any order ... if you don't change the index value itself ... the result will be always the same.

Method Summary

Modifier and Type	Method and Description
String	getId()
void	setQueryPart(int nPosition, EQueryPartBinding eBinding, EQueryPartOperation eOperation, String sAttribute, Object aValue) define one part of the query ...

Method Detail

getId

String getId()
      throws Exception

Returns:

the internal ID of this query. Those ID was define by YOU ... because you have to create queries by calling IDB.prepareQuery(sID) :-)

Throws:

Exception

setQueryPart

void setQueryPart(int nPosition,
                  EQueryPartBinding eBinding,
                  EQueryPartOperation eOperation,
                  String sAttribute,
                  Object aValue)
           throws Exception

define one part of the query ... or set a new value there.

Parameters:

nPosition - [IN] the position of that part within the query. Must start at 0.

eBinding - [IN] define the boolean operator (and/or) against the part placed at nPosition-1. Will be ignored if nPosition==0.

eOperation - [IN] define the operation used by this part (==, like, between ...)

sAttribute - [IN] the name of the attribute to be checked here.

aValue - [IN] the search value itself. Note For the given value there exists some conditions ... a) if eOperation=like it must be from type String. b) if eOperation=between it must be from type BetweenQueryRange.

Throws:

Exception