/*******************************************************************************
* Copyright (c) 1998, 2008 Oracle. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Oracle - initial API and implementation from Oracle TopLink
* Phillip Ross - LIMIT/OFFSET syntax support
******************************************************************************/
package org.eclipse.persistence.platform.database;
import java.io.*;
import java.util.*;
import org.eclipse.persistence.exceptions.ValidationException;
import org.eclipse.persistence.expressions.ExpressionOperator;
import org.eclipse.persistence.internal.databaseaccess.DatabaseCall;
import org.eclipse.persistence.internal.databaseaccess.FieldTypeDefinition;
import org.eclipse.persistence.internal.expressions.ExpressionSQLPrinter;
import org.eclipse.persistence.internal.expressions.RelationExpression;
import org.eclipse.persistence.internal.expressions.SQLSelectStatement;
import org.eclipse.persistence.internal.helper.*;
import org.eclipse.persistence.queries.ValueReadQuery;
import org.eclipse.persistence.tools.schemaframework.FieldDefinition;
/**
* <p><b>Purpose</b>: Provides Postgres specific behavior.
* <p><b>Responsibilities</b>:<ul>
* <li> Native SQL for Date, Time, & Timestamp.
* <li> Native sequencing.
* <li> Mapping of class types to database types for the schema framework.
* <li> Pessimistic locking.
* <li> Platform specific operators.
* <li> LIMIT/OFFSET query syntax for select statements.
* </ul>
*
* @since OracleAS TopLink 10<i>g</i> (10.1.3)
*/
public class PostgreSQLPlatform extends DatabasePlatform {
private static final String LIMIT = " LIMIT ";
private static final String OFFSET = " OFFSET ";
public PostgreSQLPlatform() {
super();
this.pingSQL = "SELECT 1";
}
/**
* Appends a Boolean value.
* Refer to : http://www.postgresql.org/docs/8.0/static/datatype-boolean.html
* In PostgreSQL the following are the values that
* are value for a boolean field
* Valid literal values for the "true" state are:
* TRUE, 't', 'true', 'y', 'yes', '1'
* Valid literal values for the false" state are :
* FALSE, 'f', 'false', 'n', 'no', '0'
*
* To be consistent with the other data platforms we are using the values
* '1' and '0' for true and false states of a boolean field.
*/
protected void appendBoolean(Boolean bool, Writer writer) throws IOException {
if (bool.booleanValue()) {
writer.write("\'1\'");
} else {
writer.write("\'0\'");
}
}
/**
* INTERNAL:
* Use the JDBC maxResults and firstResultIndex setting to compute a value to use when
* limiting the results of a query in SQL. These limits tend to be used in two ways.
*
* 1. MaxRows is the index of the last row to be returned (like JDBC maxResults)
* 2. MaxRows is the number of rows to be returned
*
* PostGreSQL uses case #2 and therefore the maxResults has to be altered based on the firstResultIndex
*
* @param readQuery
* @param firstResultIndex
* @param maxResults
*
* @see org.eclipse.persistence.platform.database.MySQLPlatform
*/
@Override
public int computeMaxRowsForSQL(int firstResultIndex, int maxResults){
return maxResults - ((firstResultIndex >= 0) ? firstResultIndex : 0);
}
/**
* INTERNAL:
* Initialize any platform-specific operators
*/
protected void initializePlatformOperators() {
super.initializePlatformOperators();
addOperator(ExpressionOperator.simpleLogicalNoParens(ExpressionOperator.Concat, "||"));
addOperator(ExpressionOperator.simpleTwoArgumentFunction(ExpressionOperator.Nvl, "COALESCE"));
addOperator(operatorLocate());
addOperator(toNumberOperator());
}
/**
* INTERNAL:
* Postgres to_number has two arguments, as fix format argument.
*/
protected ExpressionOperator toNumberOperator() {
ExpressionOperator exOperator = new ExpressionOperator();
exOperator.setType(ExpressionOperator.FunctionOperator);
exOperator.setSelector(ExpressionOperator.ToNumber);
Vector v = org.eclipse.persistence.internal.helper.NonSynchronizedVector.newInstance(2);
v.addElement("TO_NUMBER(");
v.addElement(", '999999999.9999')");
exOperator.printsAs(v);
exOperator.bePrefix();
exOperator.setNodeClass(ClassConstants.FunctionExpression_Class);
return exOperator;
}
/**
* INTERNAL:
* This method returns the query to select the timestamp from the server
* for Derby.
*/
public ValueReadQuery getTimestampQuery() {
if (timestampQuery == null) {
timestampQuery = new ValueReadQuery();
timestampQuery.setSQLString("SELECT NOW()");
}
return timestampQuery;
}
/**
* This method is used to print the output parameter token when stored
* procedures are called
*/
public String getInOutputProcedureToken() {
return "OUT";
}
/**
* This is required in the construction of the stored procedures with
* output parameters
*/
public boolean shouldPrintOutputTokenAtStart() {
//TODO: Check with the reviewer where this is used
return false;
}
/**
* INTERNAL:
* Answers whether platform is Derby
*/
public boolean isPostgreSQL() {
return true;
}
/**
* INTERNAL:
*/
protected String getCreateTempTableSqlSuffix() {
// http://pgsqld.active-venture.com/sql-createtable.html
return " ON COMMIT PRESERVE ROWS";
}
/**
* INTERNAL:
* Indicates whether locking OF clause should print alias for field.
* Example:
* on Oracle platform (method returns false):
* SELECT ADDRESS_ID, ... FROM ADDRESS T1 WHERE (T1.ADDRESS_ID = ?) FOR UPDATE OF T1.ADDRESS_ID
* on Postgres platform (method returns true):
* SELECT ADDRESS_ID, ... FROM ADDRESS T1 WHERE (T1.ADDRESS_ID = ?) FOR UPDATE OF T1
*/
public boolean shouldPrintAliasForUpdate() {
return true;
}
/**
* INTERNAL:
* Indicates whether the platform supports identity.
* This method is to be used *ONLY* by sequencing classes
*/
public boolean supportsIdentity() {
return true;
}
/**
* INTERNAL:
* Returns query used to read back the value generated by Identity.
* This method is called when identity NativeSequence is connected,
* the returned query used until the sequence is disconnected.
* If the platform supportsIdentity then (at least) one of buildSelectQueryForIdentity
* methods should return non-null query.
*/
public ValueReadQuery buildSelectQueryForIdentity() {
ValueReadQuery selectQuery = new ValueReadQuery();
selectQuery.setSQLString("select lastval()");
return selectQuery;
}
/**
* INTERNAL:
* Indicates whether the platform supports sequence objects.
* This method is to be used *ONLY* by sequencing classes
*/
public boolean supportsSequenceObjects() {
return true;
}
/**
* INTERNAL:
* Returns query used to read value generated by sequence object (like Oracle sequence).
* This method is called when sequence object NativeSequence is connected,
* the returned query used until the sequence is disconnected.
* If the platform supportsSequenceObjects then (at least) one of buildSelectQueryForSequenceObject
* methods should return non-null query.
*/
public ValueReadQuery buildSelectQueryForSequenceObject(String seqName, Integer size) {
return new ValueReadQuery("select nextval(\'" + getQualifiedName(seqName) + "\')");
}
/**
* INTERNAL:
*/
protected String getCreateTempTableSqlBodyForTable(DatabaseTable table) {
// returning null includes fields of the table in body
// see javadoc of DatabasePlatform#getCreateTempTableSqlBodyForTable(DataBaseTable)
// for details
return null;
}
/**
* INTERNAL:
* Append the receiver's field 'identity' constraint clause to a writer
*/
public void printFieldIdentityClause(Writer writer) throws ValidationException {
try {
writer.write(" SERIAL");
} catch (IOException ioException) {
throw ValidationException.fileError(ioException);
}
}
protected Hashtable buildFieldTypes() {
Hashtable fieldTypeMapping = new Hashtable();
fieldTypeMapping.put(Boolean.class, new FieldTypeDefinition("BOOLEAN", false));
fieldTypeMapping.put(Integer.class, new FieldTypeDefinition("INTEGER", false));
fieldTypeMapping.put(Long.class, new FieldTypeDefinition("BIGINT", false));
fieldTypeMapping.put(Float.class, new FieldTypeDefinition("FLOAT", false));
fieldTypeMapping.put(Double.class, new FieldTypeDefinition("FLOAT", false));
fieldTypeMapping.put(Short.class, new FieldTypeDefinition("SMALLINT", false));
fieldTypeMapping.put(Byte.class, new FieldTypeDefinition("SMALLINT", false));
fieldTypeMapping.put(java.math.BigInteger.class, new FieldTypeDefinition("BIGINT", false));
fieldTypeMapping.put(java.math.BigDecimal.class, new FieldTypeDefinition("DECIMAL",38));
fieldTypeMapping.put(Number.class, new FieldTypeDefinition("DECIMAL",38));
fieldTypeMapping.put(String.class, new FieldTypeDefinition("VARCHAR", 255));
fieldTypeMapping.put(Character.class, new FieldTypeDefinition("CHAR", 1));
fieldTypeMapping.put(Byte[].class, new FieldTypeDefinition("BYTEA", false));
fieldTypeMapping.put(Character[].class, new FieldTypeDefinition("TEXT"));
fieldTypeMapping.put(byte[].class, new FieldTypeDefinition("BYTEA", false));
fieldTypeMapping.put(char[].class, new FieldTypeDefinition("TEXT"));
fieldTypeMapping.put(java.sql.Blob.class, new FieldTypeDefinition("BYTEA"));
fieldTypeMapping.put(java.sql.Clob.class, new FieldTypeDefinition("TEXT"));
fieldTypeMapping.put(java.sql.Date.class, new FieldTypeDefinition("DATE", false));
fieldTypeMapping.put(java.sql.Time.class, new FieldTypeDefinition("TIME", false));
fieldTypeMapping.put(java.sql.Timestamp.class, new FieldTypeDefinition("TIMESTAMP", false));
return fieldTypeMapping;
}
/**
* INTERNAL:
* Override the default locate operator
*/
protected ExpressionOperator operatorLocate() {
ExpressionOperator result = new ExpressionOperator();
result.setSelector(ExpressionOperator.Locate);
Vector v = new Vector(3);
v.addElement("STRPOS(");
v.addElement(", ");
v.addElement(")");
result.printsAs(v);
result.bePrefix();
result.setNodeClass(RelationExpression.class);
return result;
}
/**
* INTERNAL:
*/
public boolean supportsGlobalTempTables() {
return true;
}
/**
* INTERNAL:
*/
protected String getCreateTempTableSqlPrefix() {
return "CREATE GLOBAL TEMPORARY TABLE ";
}
/**
* INTERNAL:
* returns the maximum number of characters that can be used in a field
* name on this platform.
*/
public int getMaxFieldNameSize() {
// The system uses no more than NAMEDATALEN-1 characters of an identifier; longer names can be written in commands,
// but they will be truncated. By default, NAMEDATALEN is 64 so the maximum identifier length is 63 (but at the time PostgreSQL
// is built, NAMEDATALEN can be changed in src/include/postgres_ext.h).
// http://www.postgresql.org/docs/7.3/interactive/sql-syntax.html#SQL-SYNTAX-IDENTIFIERS
return 63;
}
// http://www.postgresql.org/docs/8.1/interactive/plpgsql-declarations.html
/**
* INTERNAL:
* Used for sp calls.
*/
public String getProcedureBeginString() {
return "AS $$ BEGIN ";
}
/**
* INTERNAL:
* Used for sp calls.
*/
public String getProcedureEndString() {
return "; END ; $$ LANGUAGE plpgsql;";
}
/**
* INTERNAL:
* Used for sp calls.
*/
public String getProcedureCallHeader() {
return "EXECUTE ";
}
/**
* INTERNAL
* Used for stored function calls.
*/
public String getAssignmentString() {
return ":= ";
}
public void printFieldTypeSize(Writer writer, FieldDefinition field,
FieldTypeDefinition fieldType, boolean shouldPrintFieldIdentityClause) throws IOException {
if(!shouldPrintFieldIdentityClause) {
super.printFieldTypeSize(writer, field, fieldType, shouldPrintFieldIdentityClause);
}
}
public void printFieldUnique(Writer writer, boolean shouldPrintFieldIdentityClause) throws IOException {
if(!shouldPrintFieldIdentityClause) {
super.printFieldUnique(writer, shouldPrintFieldIdentityClause);
}
}
/**
* JDBC defines and outer join syntax, many drivers do not support this. So we normally avoid it.
*/
public boolean shouldUseJDBCOuterJoinSyntax() {
return false;
}
/**
* INTERNAL:
* Override this method if the platform supports sequence objects.
* Returns sql used to create sequence object in the database.
*/
public Writer buildSequenceObjectCreationWriter(Writer writer, String fullSeqName, int increment, int start) throws IOException {
writer.write("CREATE SEQUENCE ");
writer.write(fullSeqName);
if (increment != 1) {
writer.write(" INCREMENT BY " + increment);
}
writer.write(" START WITH " + start);
return writer;
}
/**
* INTERNAL:
* Override this method if the platform supports sequence objects.
* Returns sql used to delete sequence object from the database.
*/
public Writer buildSequenceObjectDeletionWriter(Writer writer, String fullSeqName) throws IOException {
writer.write("DROP SEQUENCE ");
writer.write(fullSeqName);
return writer;
}
/**
* INTERNAL:
* Override this method if the platform supports sequence objects
* and isAlterSequenceObjectSupported returns true.
* Returns sql used to alter sequence object's increment in the database.
*/
public Writer buildSequenceObjectAlterIncrementWriter(Writer writer, String fullSeqName, int increment) throws IOException {
writer.write("ALTER SEQUENCE ");
writer.write(fullSeqName);
writer.write(" INCREMENT BY " + increment);
return writer;
}
/**
* INTERNAL:
* Override this method if the platform supports sequence objects
* and it's possible to alter sequence object's increment in the database.
*/
public boolean isAlterSequenceObjectSupported() {
return true;
}
@Override
public void printSQLSelectStatement(DatabaseCall call, ExpressionSQLPrinter printer, SQLSelectStatement statement) {
int max = 0;
int firstRow = 0;
if (statement.getQuery() != null) {
max = statement.getQuery().getMaxRows();
firstRow = statement.getQuery().getFirstResult();
}
if (max <= 0 || !(this.shouldUseRownumFiltering())) {
super.printSQLSelectStatement(call, printer, statement);
return;
}
statement.setUseUniqueFieldAliases(true);
call.setFields(statement.printSQL(printer));
printer.printString(LIMIT);
printer.printParameter(DatabaseCall.MAXROW_FIELD);
printer.printString(OFFSET);
printer.printParameter(DatabaseCall.FIRSTRESULT_FIELD);
call.setIgnoreFirstRowMaxResultsSettings(true);
}
}