Let me explain you Jason.
Since I had an issue with my previous example I thought of creating a new service....which is below.
'Zuserid' field is the Key..
My MetaData when I used URL : http://domain:port/sap/opu/odata/sap/ZUI5_SAMPLEUSERINFO_SRV/$metadata
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<edmx:Edmx xmlns:edmx="http://schemas.microsoft.com/ado/2007/06/edmx" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata"xmlns:sap="http://www.sap.com/Protocols/SAPData" Version="1.0">
<edmx:DataServices m:DataServiceVersion="2.0">
<Schema xmlns="http://schemas.microsoft.com/ado/2008/09/edm" Namespace="ZUI5_SAMPLEUSERINFO_SRV" xml:lang="en" sap:schema-version="0000">
<EntityType Name="UserInfoSample" sap:content-version="1">
<Key>
<PropertyRef Name="Zuserid"/>
</Key>
<Property Name="Zuserid" Type="Edm.String" Nullable="false" MaxLength="12" sap:label="Chgd by" sap:creatable="false" sap:updatable="false" sap:sortable="false"/>
<Property Name="Zaddr" Type="Edm.String" Nullable="false" MaxLength="50" sap:label="Address" sap:creatable="false" sap:updatable="false" sap:sortable="false"sap:filterable="false"/>
<Property Name="Zcountry" Type="Edm.String" Nullable="false" MaxLength="50" sap:label="Address" sap:creatable="false" sap:updatable="false" sap:sortable="false"sap:filterable="false"/>
</EntityType>
<EntityContainer Name="ZUI5_SAMPLEUSERINFO_SRV_Entities" m:IsDefaultEntityContainer="true">
<EntitySet Name="UserInfoSampleSet" EntityType="ZUI5_SAMPLEUSERINFO_SRV.UserInfoSample" sap:creatable="false" sap:updatable="false" sap:deletable="false" sap:pageable="false"sap:content-version="1"/>
</EntityContainer>
<atom:link xmlns:atom="http://www.w3.org/2005/Atom" rel="self" href="http://domain:port/sap/opu/odata/sap/ZUI5_SAMPLEUSERINFO_SRV/$metadata"/>
<atom:link xmlns:atom="http://www.w3.org/2005/Atom" rel="latest-version" href="http://domain:port/sap/opu/odata/sap/ZUI5_SAMPLEUSERINFO_SRV/$metadata"/>
</Schema>
</edmx:DataServices>
</edmx:Edmx>
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Now I used URL to test my getEntity() function which I implemented and it worked fine. URL is : http://domain:port/sap/opu/odata/sap/ZUI5_SAMPLEUSERINFO_SRV/UserInfoSampleSet('123098')
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<entry xmlns="http://www.w3.org/2005/Atom" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xml:base="http://nwcedev1.amat.com:8000/sap/opu/odata/sap/ZUI5_SAMPLEUSERINFO_SRV/">
<id>
http://domain:port/sap/opu/odata/sap/ZUI5_SAMPLEUSERINFO_SRV/UserInfoSampleSet('123098')
</id>
<title type="text">UserInfoSampleSet('123098')</title>
<updated>2015-01-14T19:12:09Z</updated>
<category term="ZUI5_SAMPLEUSERINFO_SRV.UserInfoSample" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme"/>
<link href="UserInfoSampleSet('123098')" rel="self" title="UserInfoSample"/>
<content type="application/xml">
<m:properties>
<d:Zuserid>123098</d:Zuserid>
<d:Zaddr>SORENIA STREET</d:Zaddr>
<d:Zcountry>SOMANIA</d:Zcountry>
</m:properties>
</content>
</entry>
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So whatever I am able to fetch using the above url (getting ne specific record) is what I what I want to achieve using my SAPUI5 program. Please advise.