Mapeamento OneToOne

@Entity
@Table(name = "municipios", catalog = "sge", schema = "public")
public class Municipio extends Objeto implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    //@GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "id")
    private Long id;
    @Basic(optional = false)
    @Column(name = "descricao")
    private String descricao;
    @Basic(optional = false)
    @Column(name = "uf")
    private String uf;
    @Basic(optional = false)
    @Column(name = "ibge")
    private String ibge;
    @Column(name = "status")
    private String status;

    public Municipio() {
    }

@Entity
@Table(name = "escolas", catalog = "sge", schema = "public")
@BatchSize(size=0)
public class Escola extends Objeto implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    //@GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "id")
    private Long id;
    @Basic(optional = false)
    @Column(name = "razao_social")
    private String razaoSocial;
    @Basic(optional = false)
    @Column(name = "nome_fantasia")
    private String nomeFantasia;
    @Basic(optional = false)
    @Column(name = "cnpj")
    private String cnpj;
    @Column(name = "numero_inep")
    private String numeroInep;
    @Column(name = "numero_cnas")
    private String numeroCnas;
    @Column(name = "numeroCebas")
    private String numeroCebas;
    @Column(name = "dependencia_administrativa")
    private String dependenciaAdministrativa;
    @Column(name = "categoria")
    private String categoria;
    @Column(name = "predio")
    private String predio;
    @Column(name = "conveniada")
    private String conveniada;
    @Column(name = "logradouro")
    private String logradouro;
    @Column(name = "numero")
    private String numero;
    @Column(name = "complemento")
    private String complemento;
    @Column(name = "bairro")
    private String bairro;
    @JoinColumn(name="municipio", referencedColumnName="id")
    @OneToOne
    private Municipio municipio;
    @Column(name = "cep")
    private String cep;
    @Column(name = "telefone")
    private String telefone;
    @Column(name = "fax")
    private String fax;
    @Column(name = "email")
    private String email;
    @Column(name = "nome_diretor")
    private String nomeDiretor;
    @Column(name = "cpf_diretor")
    private String cpfDiretor;
    @Column(name = "telefone_diretor")
    private String telefoneDiretor;
    @Column(name = "email_diretor")
    private String emailDiretor;
    @Column(name = "observacao")
    private String observacao;
    @Column(name = "status")
    private String status;

    public Escola() {
    }

org.hibernate.exception.SQLGrammarException: Could not execute JDBC batch update
	at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:90)
	at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
	at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275)
	at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:266)
	at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:167)
	at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
	at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
	at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1027)
	at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:365)
	at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:137)
	at br.com.jd.dao.Dao.inserir(Dao.java:22)
	at br.com.jd.facade.EscolaFacade.inserir(EscolaFacade.java:22)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at flex.messaging.services.remoting.adapters.JavaAdapter.invoke(JavaAdapter.java:421)
	at flex.messaging.services.RemotingService.serviceMessage(RemotingService.java:183)
	at flex.messaging.MessageBroker.routeMessageToService(MessageBroker.java:1529)
	at flex.messaging.endpoints.AbstractEndpoint.serviceMessage(AbstractEndpoint.java:907)
	at flex.messaging.endpoints.amf.MessageBrokerFilter.invoke(MessageBrokerFilter.java:121)
	at flex.messaging.endpoints.amf.LegacyFilter.invoke(LegacyFilter.java:158)
	at flex.messaging.endpoints.amf.SessionFilter.invoke(SessionFilter.java:44)
	at flex.messaging.endpoints.amf.BatchProcessFilter.invoke(BatchProcessFilter.java:67)
	at flex.messaging.endpoints.amf.SerializationFilter.invoke(SerializationFilter.java:147)
	at flex.messaging.endpoints.BaseHTTPEndpoint.service(BaseHTTPEndpoint.java:278)
	at flex.messaging.MessageBrokerServlet.service(MessageBrokerServlet.java:322)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.sql.BatchUpdateException: Entrada em lote 0 insert into sge.public.escolas (bairro, categoria, cep, cnpj, complemento, conveniada, cpf_diretor, dependencia_administrativa, email, email_diretor, fax, logradouro, municipio, nome_diretor, nome_fantasia, numero, numeroCebas, numero_cnas, numero_inep, observacao, predio, razao_social, status, telefone, telefone_diretor, id) values (, Particular, , , , NULL, , , , , , , 125, , CSTA, , , , 123, , Proprio, COLEGIO SAO TOMAS DE AQUINO, A, , , 11) foi abortada. Chame getNextException para ver a causa.
	at org.postgresql.jdbc2.AbstractJdbc2Statement$BatchResultHandler.handleError(AbstractJdbc2Statement.java:2531)
	at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1344)
	at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:343)
	at org.postgresql.jdbc2.AbstractJdbc2Statement.executeBatch(AbstractJdbc2Statement.java:2668)
	at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:70)
	at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:268)
	... 41 more