1. add quick start usage in README.

2. delete out-of-date example data, and add new example data.

author: hanshuo

README.md

@@ -1,22 +1,131 @@
-gStore
-======
+#gStore
 
 ## gStore2.0
 
 ### Overview
-gStore is a graph-based RDF data management system (or what is commonly called a “triple store”) that maintains the graph structure of the original RDF data. Its data model is a labeled, directed multiedge graph, where each vertex corresponds to a subject or an object. We also represent a given SPARQL query by a query graph Q. Query processing involves finding subgraph matches of Q over the RDF graph G. gStore incorporates an index over the RDF graph (called VS-tree) to speed up query processing. VS-tree is a heightbalanced tree with a number of associated pruning techniques to speed up subgraph matching.
+gStore is a graph-based RDF data management system (or what is commonly called a “triple store”) that maintains the graph structure of the original [RDF](http://www.w3.org/TR/rdf11-concepts/) data. Its data model is a labeled, directed multiedge graph, where each vertex corresponds to a subject or an object. We also represent a given [SPARQL](http://www.w3.org/TR/sparql11-overview/) query by a query graph Q. Query processing involves finding subgraph matches of Q over the RDF graph G. gStore incorporates an index over the RDF graph (called VS-tree) to speed up query processing. VS-tree is a heightbalanced tree with a number of associated pruning techniques to speed up subgraph matching.
 
 ### Install Steps
-System Requirement: 64bit linux with g++, gcc, make installed.
+System Requirement: 64-bit linux server with GCC, make installed.
+*We have tested on linux server with CentOS 6.2 x86_64 and CentOS 6.6 x86_64. The version of GCC should be 4.4.7 or later.*
 
-Install gStore2.0, just with two commands. 
+You can install gStore2.0 in two commands. 
 
 1) run
-> **make lib_antlr**
 
-to compile and link the library(static) we need.
+`# make lib_antlr`
+
+to compile and link the library we need.
 
 2) run
-> **make**
+
+`# make` 
 
 to compile the gStore code and build executable "gload", "gquery", "gserver", "gclient".
+
+
+### Usage
+gStore2.0 currently includes four executables.
+
+####1. gload
+gload is used to build a new database from a RDF triple format file.
+
+`# ./gload db_name rdf_triple_file_name`
+
+For example, we build a database from LUBM_10.n3 which can be found in example folder.
+
+    [root@master Gstore]# ./gload db_LUBM10 ./example/LUBM_10.n3 
+    2015年05月21日 星期四 20时58分21秒  -0.484698 seconds
+    gload...
+    argc: 3 DB_store:db_LUBM10      RDF_data: ./example/LUBM_10.n3  
+    begin encode RDF from : ./example/LUBM_10.n3 ...
+
+####2. gquery
+gquery is used to query an exsisting database with SPARQL files.
+
+`#./gquery db_name`
+
+The program shows a command prompt: inputting a file name which can be interpreted as a single SPARQL query. When the program finish answering the query, it shows the command prompt again. 
+*gStore2.0 only support simple “select” queries now.*
+
+We also take LUBM_10 as an example.
+
+    [root@master Gstore]# ./gquery db_LUBM10/
+    gquery...
+    argc: 2 DB_store:db_LUBM10/
+    loadTree...
+    LRUCache initial...
+    LRUCache initial finish
+    finish loadCache
+    finish loadEntityID2FileLineMap
+    open KVstore
+    finish load
+    finish loading
+    please input query file path:
+    ./example/LUBM_q0.txt
+    ... ...
+    Total time used: 4ms.
+    final result is : 
+    <http://www.Department0.University0.edu/FullProfessor0>
+    <http://www.Department1.University0.edu/FullProfessor0>
+    <http://www.Department2.University0.edu/FullProfessor0>
+    <http://www.Department3.University0.edu/FullProfessor0>
+    <http://www.Department4.University0.edu/FullProfessor0>
+    <http://www.Department5.University0.edu/FullProfessor0>
+    <http://www.Department6.University0.edu/FullProfessor0>
+    <http://www.Department7.University0.edu/FullProfessor0>
+    <http://www.Department8.University0.edu/FullProfessor0>
+    <http://www.Department9.University0.edu/FullProfessor0>
+    <http://www.Department10.University0.edu/FullProfessor0>
+    <http://www.Department11.University0.edu/FullProfessor0>
+    <http://www.Department12.University0.edu/FullProfessor0>
+    <http://www.Department13.University0.edu/FullProfessor0>
+    <http://www.Department14.University0.edu/FullProfessor0>
+
+
+####3. gserver
+gserver is a daemon. It should be launched first when accessing gStore by gclient or API. It communicates with client through socket. 
+
+    [root@master Gstore]# ./gserver 
+    port=3305
+    Wait for input...
+
+You can also assign a custom port for listening.
+
+    [root@master Gstore]# ./gserver 3307
+    port=3307
+    Wait for input...
+
+####4. gclient
+gclient is designed as a client to send commands and receive feedbacks.
+
+    [root@master Gstore]# ./gclient 
+    ip=127.0.0.1 port=3305
+    ->
+
+We can use these following commands now:
+
+`->import db_name rdf_triple_file_name;`
+build a database from RDF triple file.
+
+`->load db_name;`
+load an exsisting database.
+
+`->unload db_name;`
+unload database, but will not delete it on disk, you can load it next time.
+
+`->query query_file_name;`
+query the current database with a SPARQL query file.
+
+`->show datbases;`
+show the current database's name.
+
+`->insert db_name rdf_triple_file_name;`
+insert a handful of new RDF triples to the orginal database.
+
+Note that each command ends with ";".
+
+####5. API
+We provide JAVA and C++ API for accessing gStore now. Please refer to example codes in `api/cpp/example` and `api/java/example`.
+
+

example/LUBM_q0.txt

@@ -0,0 +1,4 @@
+select ?x where
+{
+	?x	<ub:name>	<FullProfessor0>.
+}

example/LUBM_q1.txt

@@ -0,0 +1,9 @@
+select ?x where
+{
+?x	<rdf:type>	<ub:GraduateStudent>.
+?y	<rdf:type>	<ub:University>.
+?z	<rdf:type>	<ub:Department>.
+?x	<ub:memberOf>	?z.
+?z	<ub:subOrganizationOf>	?y.
+?x	<ub:undergraduateDegreeFrom>	?y.
+}

example/LUBM_q2.txt

@@ -0,0 +1,5 @@
+select ?x where
+{
+?x	<rdf:type>	<ub:Course>.
+?x	<ub:name>	?y.
+}

example/query_test

@@ -0,0 +1,4 @@
+select ?x1 where
+{
+<!!!>	<>	?x1.
+}

example/yago_10000_a

@@ -1,3 +1,6 @@
+@prefix rdf: <http://rdf/>.
+@prefix rdfs: <http://rdfs/>.
+@prefix y: <http://y/>.
 <!!!>	y:created	<Louden_Up_Now>.
 <!!!>	y:created	<!!!_(album)>.
 <!!!>	y:created	<Take_Ecstasy_with_Me%2FGet_Up>.