//$Id: DB2Dialect.java,v 1.38 2005/12/08 02:41:15 oneovthafew Exp $
package org.hibernate.dialect;
import java.sql.CallableStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import org.hibernate.Hibernate;
import org.hibernate.cfg.Environment;
import org.hibernate.dialect.function.NoArgSQLFunction;
import org.hibernate.dialect.function.SQLFunctionTemplate;
import org.hibernate.dialect.function.StandardSQLFunction;
import org.hibernate.dialect.function.VarArgsSQLFunction;
/**
* An SQL dialect for DB2.
* @author Gavin King
*/
public class DB2Dialect extends Dialect {
public DB2Dialect() {
super();
registerColumnType( Types.BIT, "smallint" );
registerColumnType( Types.BIGINT, "bigint" );
registerColumnType( Types.SMALLINT, "smallint" );
registerColumnType( Types.TINYINT, "smallint" );
registerColumnType( Types.INTEGER, "integer" );
registerColumnType( Types.CHAR, "char(1)" );
registerColumnType( Types.VARCHAR, "varchar($l)" );
registerColumnType( Types.FLOAT, "float" );
registerColumnType( Types.DOUBLE, "double" );
registerColumnType( Types.DATE, "date" );
registerColumnType( Types.TIME, "time" );
registerColumnType( Types.TIMESTAMP, "timestamp" );
registerColumnType( Types.VARBINARY, "varchar($l) for bit data" );
registerColumnType( Types.NUMERIC, "numeric($p,$s)" );
registerColumnType( Types.BLOB, "blob($l)" );
registerColumnType( Types.CLOB, "clob($l)" );
registerFunction("abs", new StandardSQLFunction("abs") );
registerFunction("absval", new StandardSQLFunction("absval") );
registerFunction("sign", new StandardSQLFunction("sign", Hibernate.INTEGER) );
registerFunction("ceiling", new StandardSQLFunction("ceiling") );
registerFunction("ceil", new StandardSQLFunction("ceil") );
registerFunction("floor", new StandardSQLFunction("floor") );
registerFunction("round", new StandardSQLFunction("round") );
registerFunction("acos", new StandardSQLFunction("acos", Hibernate.DOUBLE) );
registerFunction("asin", new StandardSQLFunction("asin", Hibernate.DOUBLE) );
registerFunction("atan", new StandardSQLFunction("atan", Hibernate.DOUBLE) );
registerFunction("cos", new StandardSQLFunction("cos", Hibernate.DOUBLE) );
registerFunction("cot", new StandardSQLFunction("cot", Hibernate.DOUBLE) );
registerFunction("degrees", new StandardSQLFunction("degrees", Hibernate.DOUBLE) );
registerFunction("exp", new StandardSQLFunction("exp", Hibernate.DOUBLE) );
registerFunction("float", new StandardSQLFunction("float", Hibernate.DOUBLE) );
registerFunction("hex", new StandardSQLFunction("hex", Hibernate.STRING) );
registerFunction("ln", new StandardSQLFunction("ln", Hibernate.DOUBLE) );
registerFunction("log", new StandardSQLFunction("log", Hibernate.DOUBLE) );
registerFunction("log10", new StandardSQLFunction("log10", Hibernate.DOUBLE) );
registerFunction("radians", new StandardSQLFunction("radians", Hibernate.DOUBLE) );
registerFunction("rand", new NoArgSQLFunction("rand", Hibernate.DOUBLE) );
registerFunction("sin", new StandardSQLFunction("sin", Hibernate.DOUBLE) );
registerFunction("soundex", new StandardSQLFunction("soundex", Hibernate.STRING) );
registerFunction("sqrt", new StandardSQLFunction("sqrt", Hibernate.DOUBLE) );
registerFunction("stddev", new StandardSQLFunction("stddev", Hibernate.DOUBLE) );
registerFunction("tan", new StandardSQLFunction("tan", Hibernate.DOUBLE) );
registerFunction("variance", new StandardSQLFunction("variance", Hibernate.DOUBLE) );
registerFunction("julian_day", new StandardSQLFunction("julian_day", Hibernate.INTEGER) );
registerFunction("microsecond", new StandardSQLFunction("microsecond", Hibernate.INTEGER) );
registerFunction("midnight_seconds", new StandardSQLFunction("midnight_seconds", Hibernate.INTEGER) );
registerFunction("minute", new StandardSQLFunction("minute", Hibernate.INTEGER) );
registerFunction("month", new StandardSQLFunction("month", Hibernate.INTEGER) );
registerFunction("monthname", new StandardSQLFunction("monthname", Hibernate.STRING) );
registerFunction("quarter", new StandardSQLFunction("quarter", Hibernate.INTEGER) );
registerFunction("hour", new StandardSQLFunction("hour", Hibernate.INTEGER) );
registerFunction("second", new StandardSQLFunction("second", Hibernate.INTEGER) );
registerFunction("current_date", new NoArgSQLFunction("current date", Hibernate.DATE, false) );
registerFunction("date", new StandardSQLFunction("date", Hibernate.DATE) );
registerFunction("day", new StandardSQLFunction("day", Hibernate.INTEGER) );
registerFunction("dayname", new StandardSQLFunction("dayname", Hibernate.STRING) );
registerFunction("dayofweek", new StandardSQLFunction("dayofweek", Hibernate.INTEGER) );
registerFunction("dayofweek_iso", new StandardSQLFunction("dayofweek_iso", Hibernate.INTEGER) );
registerFunction("dayofyear", new StandardSQLFunction("dayofyear", Hibernate.INTEGER) );
registerFunction("days", new StandardSQLFunction("days", Hibernate.LONG) );
registerFunction("current_time", new NoArgSQLFunction("current time", Hibernate.TIME, false) );
registerFunction("time", new StandardSQLFunction("time", Hibernate.TIME) );
registerFunction("current_timestamp", new NoArgSQLFunction("current timestamp", Hibernate.TIMESTAMP, false) );
registerFunction("timestamp", new StandardSQLFunction("timestamp", Hibernate.TIMESTAMP) );
registerFunction("timestamp_iso", new StandardSQLFunction("timestamp_iso", Hibernate.TIMESTAMP) );
registerFunction("week", new StandardSQLFunction("week", Hibernate.INTEGER) );
registerFunction("week_iso", new StandardSQLFunction("week_iso", Hibernate.INTEGER) );
registerFunction("year", new StandardSQLFunction("year", Hibernate.INTEGER) );
registerFunction("double", new StandardSQLFunction("double", Hibernate.DOUBLE) );
registerFunction("varchar", new StandardSQLFunction("varchar", Hibernate.STRING) );
registerFunction("real", new StandardSQLFunction("real", Hibernate.FLOAT) );
registerFunction("bigint", new StandardSQLFunction("bigint", Hibernate.LONG) );
registerFunction("char", new StandardSQLFunction("char", Hibernate.CHARACTER) );
registerFunction("integer", new StandardSQLFunction("integer", Hibernate.INTEGER) );
registerFunction("smallint", new StandardSQLFunction("smallint", Hibernate.SHORT) );
registerFunction("digits", new StandardSQLFunction("digits", Hibernate.STRING) );
registerFunction("chr", new StandardSQLFunction("chr", Hibernate.CHARACTER) );
registerFunction("upper", new StandardSQLFunction("upper") );
registerFunction("lower", new StandardSQLFunction("lower") );
registerFunction("ucase", new StandardSQLFunction("ucase") );
registerFunction("lcase", new StandardSQLFunction("lcase") );
registerFunction("length", new StandardSQLFunction("length", Hibernate.LONG) );
registerFunction("ltrim", new StandardSQLFunction("ltrim") );
registerFunction("rtrim", new StandardSQLFunction("rtrim") );
registerFunction( "substr", new StandardSQLFunction( "substr", Hibernate.STRING ) );
registerFunction( "posstr", new StandardSQLFunction( "posstr", Hibernate.INTEGER ) );
registerFunction( "substring", new StandardSQLFunction( "substr", Hibernate.STRING ) );
registerFunction( "trim", new SQLFunctionTemplate( Hibernate.INTEGER, "ltrim(rtrim(?1))" ) );
registerFunction( "bit_length", new SQLFunctionTemplate( Hibernate.INTEGER, "length(?1)*8" ) );
registerFunction( "concat", new VarArgsSQLFunction(Hibernate.STRING, "", "||", "") );
registerFunction( "str", new SQLFunctionTemplate( Hibernate.STRING, "rtrim(char(?1))" ) );
registerKeyword("current");
registerKeyword("date");
registerKeyword("time");
registerKeyword("timestamp");
registerKeyword("fetch");
registerKeyword("first");
registerKeyword("rows");
registerKeyword("only");
getDefaultProperties().setProperty(Environment.STATEMENT_BATCH_SIZE, NO_BATCH);
}
public String getLowercaseFunction() {
return "lcase";
}
public String getAddColumnString() {
return "add column";
}
public boolean dropConstraints() {
return false;
}
public boolean supportsIdentityColumns() {
return true;
}
public String getIdentitySelectString() {
return "values identity_val_local()";
}
public String getIdentityColumnString() {
return "generated by default as identity"; //not null 
(start with 1) is implicit
}
public String getIdentityInsertString() {
return "default";
}
public String getSequenceNextValString(String sequenceName) {
return "values nextval for " + sequenceName;
}
public String getCreateSequenceString(String sequenceName) {
return "create sequence " + sequenceName;
}
public String getDropSequenceString(String sequenceName) {
return "drop sequence " + sequenceName + " restrict";
}
public boolean supportsSequences() {
return true;
}
public String getQuerySequencesString() {
return "select seqname from sysibm.syssequences";
}
public boolean supportsLimit() {
return true;
}
/*public String getLimitString(String sql, boolean hasOffset) {
StringBuffer rownumber = new StringBuffer(50)
.append(" rownumber() over(");
int orderByIndex = sql.toLowerCase().indexOf("order by");
if (orderByIndex>0) rownumber.append( sql.substring(orderByIndex) );
rownumber.append(") as row_,");
StringBuffer pagingSelect = new StringBuffer( sql.length()+100 )
.append("select * from ( ")
.append(sql)
.insert( getAfterSelectInsertPoint(sql)+16, rownumber.toString() )
.append(" ) as temp_ where row_ ");
if (hasOffset) {
pagingSelect.append("between ?+1 and ?");
}
else {
pagingSelect.append("<= ?");
}
return pagingSelect.toString();
}*/
/**
* Render the <tt>rownumber() over ( . ) as rownumber_,</tt>
* bit, that goes in the select list
*/
private String getRowNumber(String sql) {
StringBuffer rownumber = new StringBuffer(50)
.append("rownumber() over(");
int orderByIndex = sql.toLowerCase().indexOf("order by");
if ( orderByIndex>0 && !hasDistinct(sql) ) {
rownumber.append( sql.substring(orderByIndex) );
}
rownumber.append(") as rownumber_,");
return rownumber.toString();
}
public String getLimitString(String sql, boolean hasOffset) {
int startOfSelect = sql.toLowerCase().indexOf("select");
StringBuffer pagingSelect = new StringBuffer( sql.length()+100 )
.append( sql.substring(0, startOfSelect) ) //add the comment
.append("select * from ( select ") //nest the main query in an outer select
.append( getRowNumber(sql) ); //add the rownnumber bit into the outer query select list
if ( hasDistinct(sql) ) {
pagingSelect.append(" row_.* from ( ") //add another (inner) nested select
.append( sql.substring(startOfSelect) ) //add the main query
.append(" ) as row_"); //close off the inner nested select
}
else {
pagingSelect.append( sql.substring( startOfSelect + 6 ) ); //add the main query
}
pagingSelect.append(" ) as temp_ where rownumber_ ");
//add the restriction to the outer select
if (hasOffset) {
pagingSelect.append("between ?+1 and ?");
}
else {
pagingSelect.append("<= ?");
}
return pagingSelect.toString();
}
private static boolean hasDistinct(String sql) {
return sql.toLowerCase().indexOf("select distinct")>=0;
}
public String getForUpdateString() {
return " for read only with rs";
}
public boolean useMaxForLimit() {
return true;
}
public boolean supportsOuterJoinForUpdate() {
return false;
}
public boolean supportsNotNullUnique() {
return false;
}
public String getSelectClauseNullString(int sqlType) {
String literal;
switch(sqlType) {
case Types.VARCHAR:
case Types.CHAR:
literal = "'x'";
break;
case Types.DATE:
literal = "'2000-1-1'";
break;
case Types.TIMESTAMP:
literal = "'2000-1-1 00:00:00'";
break;
case Types.TIME:
literal = "'00:00:00'";
break;
default:
literal = "0";
}
return "nullif(" + literal + ',' + literal + ')';
}
public static void main(String[] args) {
System.out.println( new DB2Dialect().getLimitString("/*foo*/ select * from foos", true) );
System.out.println( new DB2Dialect().getLimitString("/*foo*/ select distinct * from foos", true) );
System.out.println( new DB2Dialect().getLimitString("/*foo*/ select * from foos foo order by foo.bar, foo.baz", true) );
System.out.println( new DB2Dialect().getLimitString("/*foo*/ select distinct * from foos foo order by foo.bar, foo.baz", true) );
}
public boolean supportsUnionAll() {
return true;
}
public int registerResultSetOutParameter(CallableStatement statement, int col) throws SQLException {
return col;
}
public ResultSet getResultSet(CallableStatement ps) throws SQLException {
boolean isResultSet = ps.execute();
// This assumes you will want to ignore any update counts
while (!isResultSet && ps.getUpdateCount() != -1) {
isResultSet = ps.getMoreResults();
}
ResultSet rs = ps.getResultSet();
// You may still have other ResultSets or update counts left to process here
// but you can't do it now or the ResultSet you just got will be closed
return rs;
}
public boolean supportsCommentOn() {
return true;
}
public boolean supportsTemporaryTables() {
return true;
}
public String getCreateTemporaryTableString() {
return "declare global temporary table";
}
public String getCreateTemporaryTablePostfix() {
return "not logged";
}
public String generateTemporaryTableName(String baseTableName) {
return "session." + super.generateTemporaryTableName(baseTableName);
}
public boolean supportsCurrentTimestampSelection() {
return true;
}
public String getCurrentTimestampSelectString() {
return "values current timestamp";
}
public boolean isCurrentTimestampSelectStringCallable() {
return false;
}
public boolean supportsParametersInInsertSelect() {
// DB2 known to not support parameters within the select
// clause of an SQL INSERT SELECT statement
return false;
}
public String getCurrentTimestampSQLFunctionName() {
return "sysdate";
}
}
posted on 2006-01-12 01:53
exo 阅读(447)
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