diff --git a/pom.xml b/pom.xml
index 3c27dc8..7beee74 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
     <groupId>eu.dnetlib.dhp</groupId>
     <artifactId>dhp-schemas</artifactId>
     <packaging>jar</packaging>
-    <version>2.2.6-SNAPSHOT</version>
+    <version>2.3.6-SNAPSHOT</version>
 
     <licenses>
         <license>
@@ -287,6 +287,13 @@
                 <scope>provided</scope>
             </dependency>
 
+            <dependency>
+                <groupId>javax.persistence</groupId>
+                <artifactId>javax.persistence-api</artifactId>
+                <version>2.2</version>
+                <scope>provided</scope>
+            </dependency>
+
         </dependencies>
     </dependencyManagement>
 
@@ -338,6 +345,11 @@
             <artifactId>commons-codec</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>javax.persistence</groupId>
+            <artifactId>javax.persistence-api</artifactId>
+        </dependency>
+
     </dependencies>
 
     <properties>
diff --git a/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStore.java b/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStore.java
new file mode 100644
index 0000000..99e9cea
--- /dev/null
+++ b/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStore.java
@@ -0,0 +1,119 @@
+
+package eu.dnetlib.dhp.schema.mdstore;
+
+import java.io.Serializable;
+import java.util.UUID;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "mdstores")
+public class MDStore implements Serializable {
+
+	/** */
+	private static final long serialVersionUID = 3160530489149700055L;
+
+	@Id
+	@Column(name = "id")
+	private String id;
+
+	@Column(name = "format")
+	private String format;
+
+	@Column(name = "layout")
+	private String layout;
+
+	@Column(name = "interpretation")
+	private String interpretation;
+
+	@Column(name = "datasource_name")
+	private String datasourceName;
+
+	@Column(name = "datasource_id")
+	private String datasourceId;
+
+	@Column(name = "api_id")
+	private String apiId;
+
+	public String getId() {
+		return id;
+	}
+
+	public void setId(final String id) {
+		this.id = id;
+	}
+
+	public String getFormat() {
+		return format;
+	}
+
+	public void setFormat(final String format) {
+		this.format = format;
+	}
+
+	public String getLayout() {
+		return layout;
+	}
+
+	public void setLayout(final String layout) {
+		this.layout = layout;
+	}
+
+	public String getInterpretation() {
+		return interpretation;
+	}
+
+	public void setInterpretation(final String interpretation) {
+		this.interpretation = interpretation;
+	}
+
+	public String getDatasourceName() {
+		return datasourceName;
+	}
+
+	public void setDatasourceName(final String datasourceName) {
+		this.datasourceName = datasourceName;
+	}
+
+	public String getDatasourceId() {
+		return datasourceId;
+	}
+
+	public void setDatasourceId(final String datasourceId) {
+		this.datasourceId = datasourceId;
+	}
+
+	public String getApiId() {
+		return apiId;
+	}
+
+	public void setApiId(final String apiId) {
+		this.apiId = apiId;
+	}
+
+	public static MDStore newInstance(
+		final String format, final String layout, final String interpretation) {
+		return newInstance(format, layout, interpretation, null, null, null);
+	}
+
+	public static MDStore newInstance(
+		final String format,
+		final String layout,
+		final String interpretation,
+		final String dsName,
+		final String dsId,
+		final String apiId) {
+		final MDStore md = new MDStore();
+		md.setId("md-" + UUID.randomUUID());
+		md.setFormat(format);
+		md.setLayout(layout);
+		md.setInterpretation(interpretation);
+		md.setDatasourceName(dsName);
+		md.setDatasourceId(dsId);
+		md.setApiId(apiId);
+		return md;
+	}
+}
diff --git a/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStoreCurrentVersion.java b/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStoreCurrentVersion.java
new file mode 100644
index 0000000..e741c43
--- /dev/null
+++ b/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStoreCurrentVersion.java
@@ -0,0 +1,51 @@
+
+package eu.dnetlib.dhp.schema.mdstore;
+
+import java.io.Serializable;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "mdstore_current_versions")
+public class MDStoreCurrentVersion implements Serializable {
+
+	/** */
+	private static final long serialVersionUID = -4757725888593745773L;
+
+	@Id
+	@Column(name = "mdstore")
+	private String mdstore;
+
+	@Column(name = "current_version")
+	private String currentVersion;
+
+	public String getMdstore() {
+		return mdstore;
+	}
+
+	public void setMdstore(final String mdstore) {
+		this.mdstore = mdstore;
+	}
+
+	public String getCurrentVersion() {
+		return currentVersion;
+	}
+
+	public void setCurrentVersion(final String currentVersion) {
+		this.currentVersion = currentVersion;
+	}
+
+	public static MDStoreCurrentVersion newInstance(final String mdId, final String versionId) {
+		final MDStoreCurrentVersion cv = new MDStoreCurrentVersion();
+		cv.setMdstore(mdId);
+		cv.setCurrentVersion(versionId);
+		return cv;
+	}
+
+	public static MDStoreCurrentVersion newInstance(final MDStoreVersion v) {
+		return newInstance(v.getMdstore(), v.getId());
+	}
+}
diff --git a/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStoreVersion.java b/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStoreVersion.java
new file mode 100644
index 0000000..d6f62ce
--- /dev/null
+++ b/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStoreVersion.java
@@ -0,0 +1,99 @@
+
+package eu.dnetlib.dhp.schema.mdstore;
+
+import java.io.Serializable;
+import java.util.Date;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+import javax.persistence.Temporal;
+import javax.persistence.TemporalType;
+
+@Entity
+@Table(name = "mdstore_versions")
+public class MDStoreVersion implements Serializable {
+
+	/** */
+	private static final long serialVersionUID = -4763494442274298339L;
+
+	@Id
+	@Column(name = "id")
+	private String id;
+
+	@Column(name = "mdstore")
+	private String mdstore;
+
+	@Column(name = "writing")
+	private boolean writing;
+
+	@Column(name = "readcount")
+	private int readCount = 0;
+
+	@Column(name = "lastupdate")
+	@Temporal(TemporalType.TIMESTAMP)
+	private Date lastUpdate;
+
+	@Column(name = "size")
+	private long size = 0;
+
+	public static MDStoreVersion newInstance(final String mdId, final boolean writing) {
+		final MDStoreVersion t = new MDStoreVersion();
+		t.setId(mdId + "-" + new Date().getTime());
+		t.setMdstore(mdId);
+		t.setLastUpdate(null);
+		t.setWriting(writing);
+		t.setReadCount(0);
+		t.setSize(0);
+		return t;
+	}
+
+	public String getId() {
+		return id;
+	}
+
+	public void setId(final String id) {
+		this.id = id;
+	}
+
+	public String getMdstore() {
+		return mdstore;
+	}
+
+	public void setMdstore(final String mdstore) {
+		this.mdstore = mdstore;
+	}
+
+	public boolean isWriting() {
+		return writing;
+	}
+
+	public void setWriting(final boolean writing) {
+		this.writing = writing;
+	}
+
+	public int getReadCount() {
+		return readCount;
+	}
+
+	public void setReadCount(final int readCount) {
+		this.readCount = readCount;
+	}
+
+	public Date getLastUpdate() {
+		return lastUpdate;
+	}
+
+	public void setLastUpdate(final Date lastUpdate) {
+		this.lastUpdate = lastUpdate;
+	}
+
+	public long getSize() {
+		return size;
+	}
+
+	public void setSize(final long size) {
+		this.size = size;
+	}
+}
diff --git a/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStoreWithInfo.java b/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStoreWithInfo.java
new file mode 100644
index 0000000..7367890
--- /dev/null
+++ b/src/main/java/eu/dnetlib/dhp/schema/mdstore/MDStoreWithInfo.java
@@ -0,0 +1,143 @@
+
+package eu.dnetlib.dhp.schema.mdstore;
+
+import java.io.Serializable;
+import java.util.Date;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+import javax.persistence.Temporal;
+import javax.persistence.TemporalType;
+
+@Entity
+@Table(name = "mdstores_with_info")
+public class MDStoreWithInfo implements Serializable {
+
+	/** */
+	private static final long serialVersionUID = -8445784770687571492L;
+
+	@Id
+	@Column(name = "id")
+	private String id;
+
+	@Column(name = "format")
+	private String format;
+
+	@Column(name = "layout")
+	private String layout;
+
+	@Column(name = "interpretation")
+	private String interpretation;
+
+	@Column(name = "datasource_name")
+	private String datasourceName;
+
+	@Column(name = "datasource_id")
+	private String datasourceId;
+
+	@Column(name = "api_id")
+	private String apiId;
+
+	@Column(name = "current_version")
+	private String currentVersion;
+
+	@Column(name = "lastupdate")
+	@Temporal(TemporalType.TIMESTAMP)
+	private Date lastUpdate;
+
+	@Column(name = "size")
+	private long size = 0;
+
+	@Column(name = "n_versions")
+	private long numberOfVersions = 0;
+
+	public String getId() {
+		return id;
+	}
+
+	public void setId(final String id) {
+		this.id = id;
+	}
+
+	public String getFormat() {
+		return format;
+	}
+
+	public void setFormat(final String format) {
+		this.format = format;
+	}
+
+	public String getLayout() {
+		return layout;
+	}
+
+	public void setLayout(final String layout) {
+		this.layout = layout;
+	}
+
+	public String getInterpretation() {
+		return interpretation;
+	}
+
+	public void setInterpretation(final String interpretation) {
+		this.interpretation = interpretation;
+	}
+
+	public String getDatasourceName() {
+		return datasourceName;
+	}
+
+	public void setDatasourceName(final String datasourceName) {
+		this.datasourceName = datasourceName;
+	}
+
+	public String getDatasourceId() {
+		return datasourceId;
+	}
+
+	public void setDatasourceId(final String datasourceId) {
+		this.datasourceId = datasourceId;
+	}
+
+	public String getApiId() {
+		return apiId;
+	}
+
+	public void setApiId(final String apiId) {
+		this.apiId = apiId;
+	}
+
+	public String getCurrentVersion() {
+		return currentVersion;
+	}
+
+	public void setCurrentVersion(final String currentVersion) {
+		this.currentVersion = currentVersion;
+	}
+
+	public Date getLastUpdate() {
+		return lastUpdate;
+	}
+
+	public void setLastUpdate(final Date lastUpdate) {
+		this.lastUpdate = lastUpdate;
+	}
+
+	public long getSize() {
+		return size;
+	}
+
+	public void setSize(final long size) {
+		this.size = size;
+	}
+
+	public long getNumberOfVersions() {
+		return numberOfVersions;
+	}
+
+	public void setNumberOfVersions(final long numberOfVersions) {
+		this.numberOfVersions = numberOfVersions;
+	}
+}