diff --git a/pom.xml b/pom.xml
index 3ee36d2..fb7697d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -72,6 +72,11 @@
       <artifactId>json</artifactId>
       <version>20220924</version>
     </dependency>
+    <dependency>
+    <groupId>org.apache.commons</groupId>
+    <artifactId>commons-collections4</artifactId>
+    <version>4.4</version>
+  </dependency>
 
   </dependencies>
 
diff --git a/src/main/java/org/leolo/nrdatad/App.java b/src/main/java/org/leolo/nrdatad/App.java
index 2292666..96d70aa 100644
--- a/src/main/java/org/leolo/nrdatad/App.java
+++ b/src/main/java/org/leolo/nrdatad/App.java
@@ -4,13 +4,17 @@ package org.leolo.nrdatad;
 import org.apache.commons.cli.*;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.leolo.nrdatad.db.CORPUSDao;
 import org.leolo.nrdatad.db.DatabaseManager;
 import org.leolo.nrdatad.cron.ReferenceDataJob;
+import org.leolo.nrdatad.model.CORPUS;
 import org.quartz.*;
 import org.quartz.impl.StdSchedulerFactory;
 
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
+import java.sql.SQLException;
+import java.util.Collection;
 
 /**
  * Hello world!
@@ -90,9 +94,27 @@ public class App {
             return;
         }
         loadCronJob();
+        new Thread(()->{testRefData();}).start();
         while(true);
     }
 
+    private void testRefData() {
+        log.atInfo().log("Testing reference data");
+        ConfigurationManager conf = ConfigurationManager.getInstance();
+        CORPUSDao.Query query = new CORPUSDao.QueryBuilder()
+                .addCrsCode("ECR").addCrsCode("VIC")
+                .addDescription("croydon").build();
+        try {
+            Collection<CORPUS> list = conf.getDatabaseManager().getCORPUSDao().executeQuery(query);
+            log.atDebug().log("{} entries found", list.size());
+            for(CORPUS corpus:list){
+                log.atDebug().log("Found entry : {}", corpus);
+            }
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     private void loadCronJob() {
         log.atDebug().log("Start loading cron jobs");
         try {
diff --git a/src/main/java/org/leolo/nrdatad/db/BaseDao.java b/src/main/java/org/leolo/nrdatad/db/BaseDao.java
index e78fd13..d0b04c8 100644
--- a/src/main/java/org/leolo/nrdatad/db/BaseDao.java
+++ b/src/main/java/org/leolo/nrdatad/db/BaseDao.java
@@ -27,4 +27,18 @@ public abstract class BaseDao {
         }
     }
 
+    protected String getQueryParams(int count){
+        if(count <= 0){
+            throw new IllegalArgumentException("count must be greater than 0");
+        }
+        StringBuilder sb = new StringBuilder();
+        for(int i=0;i<count;i++){
+            if(i>0){
+                sb.append(",");
+            }
+            sb.append("?");
+        }
+        return sb.toString();
+    }
+
 }
diff --git a/src/main/java/org/leolo/nrdatad/db/CORPUSDao.java b/src/main/java/org/leolo/nrdatad/db/CORPUSDao.java
index a0af137..f359c11 100644
--- a/src/main/java/org/leolo/nrdatad/db/CORPUSDao.java
+++ b/src/main/java/org/leolo/nrdatad/db/CORPUSDao.java
@@ -1,12 +1,10 @@
 package org.leolo.nrdatad.db;
 
+import org.apache.commons.collections4.SetUtils;
 import org.leolo.nrdatad.model.CORPUS;
 
 import java.sql.SQLException;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
+import java.util.*;
 
 public abstract class CORPUSDao extends BaseDao{
 
@@ -23,32 +21,39 @@ public abstract class CORPUSDao extends BaseDao{
         private Set<String> description = new HashSet<>();
         SearchMode searchMode = SearchMode.MATCH_ALL_GROUP;
 
-        public void setSearchMode(SearchMode searchMode) {
+        public QueryBuilder setSearchMode(SearchMode searchMode) {
             this.searchMode = searchMode;
+            return this;
         }
 
-        public void addStanox(String stanox){
+        public QueryBuilder addStanox(String stanox){
             this.stanox.add(stanox);
+            return this;
         }
 
-        public void addUicCode(String uicCode){
+        public QueryBuilder addUicCode(String uicCode){
             this.uicCode.add(uicCode);
+            return this;
         }
 
-        public void addCrsCode(String crsCode){
+        public QueryBuilder addCrsCode(String crsCode){
             this.crsCode.add(crsCode);
+            return this;
         }
 
-        public void addTiplocCode(String tiplocCode){
+        public QueryBuilder addTiplocCode(String tiplocCode){
             this.tiplocCode.add(tiplocCode);
+            return this;
         }
 
-        public void addNlcCode(String nlcCode){
+        public QueryBuilder addNlcCode(String nlcCode){
             this.nlcCode.add(nlcCode);
+            return this;
         }
 
-        public void addDescription(String description){
+        public QueryBuilder addDescription(String description){
             this.description.add(description);
+            return this;
         }
 
         public Query build(){
@@ -66,40 +71,40 @@ public abstract class CORPUSDao extends BaseDao{
         SearchMode searchMode = SearchMode.MATCH_ALL_GROUP;
 
         private Query(Set<String> stanox, Set<String> uicCode, Set<String> crsCode, Set<String> tiplocCode, Set<String> nlcCode, Set<String> description, SearchMode searchMode) {
-            this.stanox = stanox;
-            this.uicCode = uicCode;
-            this.crsCode = crsCode;
-            this.tiplocCode = tiplocCode;
-            this.nlcCode = nlcCode;
-            this.description = description;
+            this.stanox = Collections.unmodifiableSet(stanox);
+            this.uicCode = Collections.unmodifiableSet(uicCode);
+            this.crsCode = Collections.unmodifiableSet(crsCode);
+            this.tiplocCode = Collections.unmodifiableSet(tiplocCode);
+            this.nlcCode = Collections.unmodifiableSet(nlcCode);
+            this.description = Collections.unmodifiableSet(description);
             this.searchMode = searchMode;
         }
 
-        protected Set<String> getStanox() {
+        public Set<String> getStanox() {
             return stanox;
         }
 
-        protected Set<String> getUicCode() {
+        public Set<String> getUicCode() {
             return uicCode;
         }
 
-        protected Set<String> getCrsCode() {
+        public Set<String> getCrsCode() {
             return crsCode;
         }
 
-        protected Set<String> getTiplocCode() {
+        public Set<String> getTiplocCode() {
             return tiplocCode;
         }
 
-        protected Set<String> getNlcCode() {
+        public Set<String> getNlcCode() {
             return nlcCode;
         }
 
-        protected Set<String> getDescription() {
+        public Set<String> getDescription() {
             return description;
         }
 
-        protected SearchMode getSearchMode() {
+        public SearchMode getSearchMode() {
             return searchMode;
         }
     }
diff --git a/src/main/java/org/leolo/nrdatad/db/ParameterStore.java b/src/main/java/org/leolo/nrdatad/db/ParameterStore.java
new file mode 100644
index 0000000..1a4e295
--- /dev/null
+++ b/src/main/java/org/leolo/nrdatad/db/ParameterStore.java
@@ -0,0 +1,53 @@
+package org.leolo.nrdatad.db;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+public class ParameterStore extends ArrayList<String> {
+
+    @Override
+    public int indexOf(Object o) {
+        return super.indexOf(o)+1;
+    }
+
+    @Override
+    public int lastIndexOf(Object o) {
+        return super.lastIndexOf(o)+1;
+    }
+
+    @Override
+    public String get(int index) {
+        return super.get(index-1);
+    }
+
+    @Override
+    public String set(int index, String element) {
+        return super.set(index-1, element);
+    }
+
+    @Override
+    public void add(int index, String element) {
+        super.add(index-1, element);
+    }
+
+    @Override
+    public String remove(int index) {
+        return super.remove(index-1);
+    }
+
+    @Override
+    public boolean addAll(int index, Collection<? extends String> c) {
+        return super.addAll(index-1, c);
+    }
+
+    @Override
+    protected void removeRange(int fromIndex, int toIndex) {
+        super.removeRange(fromIndex-1, toIndex-1);
+    }
+
+    @Override
+    public List<String> subList(int fromIndex, int toIndex) {
+        return super.subList(fromIndex-1, toIndex-1);
+    }
+}
diff --git a/src/main/java/org/leolo/nrdatad/db/SearchMode.java b/src/main/java/org/leolo/nrdatad/db/SearchMode.java
index 28e2118..11de03c 100644
--- a/src/main/java/org/leolo/nrdatad/db/SearchMode.java
+++ b/src/main/java/org/leolo/nrdatad/db/SearchMode.java
@@ -1,7 +1,17 @@
 package org.leolo.nrdatad.db;
 
 public enum SearchMode {
+
+    /**
+     * Indicate all condition must be matched
+     */
     MATCH_ALL,
+    /**
+     * Indicate at least one condition in every group must be matched
+     */
     MATCH_ALL_GROUP,
+    /**
+     * Indicate at least one condition must be matched.
+     */
     MATCH_ANY;
 }
diff --git a/src/main/java/org/leolo/nrdatad/db/mariadb/CORPUSDao.java b/src/main/java/org/leolo/nrdatad/db/mariadb/CORPUSDao.java
index 3a2b7e6..9e26daf 100644
--- a/src/main/java/org/leolo/nrdatad/db/mariadb/CORPUSDao.java
+++ b/src/main/java/org/leolo/nrdatad/db/mariadb/CORPUSDao.java
@@ -4,13 +4,12 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.jetbrains.annotations.NotNull;
 import org.leolo.nrdatad.db.DatabaseManager;
+import org.leolo.nrdatad.db.ParameterStore;
+import org.leolo.nrdatad.db.SearchMode;
 import org.leolo.nrdatad.model.CORPUS;
 
 import java.sql.*;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Vector;
+import java.util.*;
 
 public class CORPUSDao extends org.leolo.nrdatad.db.CORPUSDao {
 
@@ -22,7 +21,77 @@ public class CORPUSDao extends org.leolo.nrdatad.db.CORPUSDao {
 
     @Override
     public Collection<CORPUS> executeQuery(org.leolo.nrdatad.db.CORPUSDao.Query query) throws SQLException {
-        return null;
+        Vector<CORPUS> corpuses = new Vector<>();
+        ParameterStore params = new ParameterStore();
+        StringBuilder sql = new StringBuilder();
+        if(query.getSearchMode()== SearchMode.MATCH_ALL_GROUP || query.getSearchMode()==SearchMode.MATCH_ANY){
+            sql.append("SELECT * FROM corpus WHERE ");
+            String keyWord;
+            if(query.getSearchMode() == SearchMode.MATCH_ALL_GROUP){
+                sql.append("1=1 ");
+                keyWord = "AND ";
+            }else{
+                sql.append("1=0 ");
+                keyWord = "OR ";
+            }
+            if(query.getStanox().size()>0){
+                sql.append(keyWord).append("stanox IN (")
+                        .append(getQueryParams(query.getStanox().size())).append(") ");
+                params.addAll(query.getStanox());
+            }
+            if(query.getUicCode().size()>0){
+                sql.append(keyWord).append("uic_code IN (")
+                        .append(getQueryParams(query.getUicCode().size())).append(") ");
+                params.addAll(query.getUicCode());
+            }
+            if(query.getCrsCode().size()>0){
+                sql.append(keyWord).append("crs_code IN (")
+                        .append(getQueryParams(query.getCrsCode().size())).append(") ");
+                params.addAll(query.getCrsCode());
+            }
+            if(query.getTiplocCode().size()>0){
+                sql.append(keyWord).append("tiploc_code IN (")
+                        .append(getQueryParams(query.getTiplocCode().size())).append(") ");
+                params.addAll(query.getTiplocCode());
+            }
+            if(query.getNlcCode().size()>0){
+                sql.append(keyWord).append("nlc_code IN(")
+                        .append(getQueryParams(query.getNlcCode().size())).append(") ");
+                params.addAll(query.getNlcCode());
+            }
+            if(query.getDescription().size()>0){
+                sql.append(keyWord).append("(");
+                boolean hasDesc = false;
+                for(String str:query.getDescription()){
+                    if(hasDesc){
+                        sql.append("OR ");
+                    }
+                    sql.append("(`desc` LIKE ? OR short_desc LIKE ? ) ");
+                    hasDesc = true;
+                    params.add("%"+str+"%");
+                    params.add("%"+str+"%");
+                }
+                sql.append(") ");
+            }
+            log.atDebug().log("SQL={}",sql);
+        }else{
+            log.always().log("Search mode {} is yet to be implemented.", query.getSearchMode());
+        }
+        try(
+                Connection conn = getConnection();
+                PreparedStatement pstmt = conn.prepareStatement(sql.toString())
+        ){
+            for(int i=1;i<=params.size();i++){
+                log.atDebug().log("Param {} = {}", i, params.get(i));
+                setString(pstmt, i, params.get(i));
+            }
+            try(ResultSet rs = pstmt.executeQuery()){
+                while(rs.next()){
+                    corpuses.add(parseCORPUS(rs));
+                }
+            }
+        }
+        return corpuses;
     }
 
     @Override
diff --git a/src/main/java/org/leolo/nrdatad/model/CORPUS.java b/src/main/java/org/leolo/nrdatad/model/CORPUS.java
index 7106ba7..5663f1a 100644
--- a/src/main/java/org/leolo/nrdatad/model/CORPUS.java
+++ b/src/main/java/org/leolo/nrdatad/model/CORPUS.java
@@ -81,4 +81,17 @@ public class CORPUS {
     public int hashCode() {
         return Objects.hash(stanoxCode, uicCode, crsCode, tiplocCode, nlcCode, longDescription, shortDescription);
     }
+
+    @Override
+    public String toString() {
+        return "CORPUS{" +
+                "stanoxCode='" + stanoxCode + '\'' +
+                ", uicCode='" + uicCode + '\'' +
+                ", crsCode='" + crsCode + '\'' +
+                ", tiplocCode='" + tiplocCode + '\'' +
+                ", nlcCode='" + nlcCode + '\'' +
+                ", longDescription='" + longDescription + '\'' +
+                ", shortDescription='" + shortDescription + '\'' +
+                '}';
+    }
 }