/*
* Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.engine;
import org.h2.util.New;
import org.h2.util.StringUtils;
import java.util.HashMap;
import java.util.regex.Pattern;
/**
* The compatibility modes. There is a fixed set of modes (for example
* PostgreSQL, MySQL). Each mode has different settings.
*/
@SuppressWarnings("unused")
public class Mode {
/**
* The name of the default mode.
*/
static final String REGULAR = "REGULAR";
private static final HashMap<String, Mode> MODES = New.hashMap();
// Modes are also documented in the features section
/**
* When enabled, aliased columns (as in SELECT ID AS I FROM TEST) return the
* alias (I in this case) in ResultSetMetaData.getColumnName() and 'null' in
* getTableName(). If disabled, the real column name (ID in this case) and
* table name is returned.
*/
public boolean aliasColumnName;
/**
* When inserting data, if a column is defined to be NOT NULL and NULL is
* inserted, then a 0 (or empty string, or the current timestamp for
* timestamp columns) value is used. Usually, this operation is not allowed
* and an exception is thrown.
*/
public boolean convertInsertNullToZero;
/**
* When converting the scale of decimal data, the number is only converted
* if the new scale is smaller than the current scale. Usually, the scale is
* converted and 0s are added if required.
*/
public boolean convertOnlyToSmallerScale;
/**
* Creating indexes in the CREATE TABLE statement is allowed using
* <code>INDEX(..)</code> or <code>KEY(..)</code>.
* Example: <code>create table test(id int primary key, name varchar(255),
* key idx_name(name));</code>
*/
public boolean indexDefinitionInCreateTable;
/**
* Meta data calls return identifiers in lower case.
*/
public boolean lowerCaseIdentifiers;
/**
* Concatenation with NULL results in NULL. Usually, NULL is treated as an
* empty string if only one of the operands is NULL, and NULL is only
* returned if both operands are NULL.
*/
public boolean nullConcatIsNull;
/**
* Identifiers may be quoted using square brackets as in [Test].
*/
public boolean squareBracketQuotedNames;
/**
* Support for the syntax
* [OFFSET .. ROW|ROWS] [FETCH FIRST .. ROW|ROWS ONLY]
* as an alternative for LIMIT .. OFFSET.
*/
public boolean supportOffsetFetch = Constants.VERSION_MINOR >= 4 ? true : false;
/**
* The system columns 'CTID' and 'OID' are supported.
*/
public boolean systemColumns;
/**
* For unique indexes, NULL is distinct. That means only one row with NULL
* in one of the columns is allowed.
*/
public boolean uniqueIndexSingleNull; //Derby/HSQLDB/MSSQLServer对于唯一索引只允许整个表中只有一条记录含有null值
/**
* When using unique indexes, multiple rows with NULL in all columns
* are allowed, however it is not allowed to have multiple rows with the
* same values otherwise.
*/
//只有Oracle为true
public boolean uniqueIndexSingleNullExceptAllColumnsAreNull; //对于唯一索引，索引记录可以全为null
/**
* Empty strings are treated like NULL values. Useful for Oracle emulation.
*/
public boolean treatEmptyStringsAsNull;
/**
* Support the pseudo-table SYSIBM.SYSDUMMY1.
*/
public boolean sysDummy1;
/**
* Text can be concatenated using '+'.
*/
public boolean allowPlusForStringConcat;
/**
* The function LOG() uses base 10 instead of E.
*/
public boolean logIsLogBase10;
/**
* SERIAL and BIGSERIAL columns are not automatically primary keys.
*/
public boolean serialColumnIsNotPK;
/**
* Swap the parameters of the CONVERT function.
*/
public boolean swapConvertFunctionParameters;
/**
* can set the isolation level using WITH {RR|RS|CS|UR}
*/
public boolean isolationLevelInSelectOrInsertStatement;
/**
* MySQL style INSERT ... ON DUPLICATE KEY UPDATE ...
*/
public boolean onDuplicateKeyUpdate;
/**
* Pattern describing the keys the java.sql.Connection.setClientInfo()
* method accepts.
*/
public Pattern supportedClientInfoPropertiesRegEx;
/**
* Support the # for column names
*/
public boolean supportPoundSymbolForColumnNames;
/**
* Whether an empty list as in "NAME IN()" results in a syntax error.
*/
public boolean prohibitEmptyInPredicate;
private final String name;
static {
Mode mode = new Mode(REGULAR);
mode.nullConcatIsNull = true;
add(mode);
mode = new Mode("DB2");
mode.aliasColumnName = true;
mode.supportOffsetFetch = true;
mode.sysDummy1 = true;
mode.isolationLevelInSelectOrInsertStatement = true;
// See
// https://www.ibm.com/support/knowledgecenter/SSEPEK_11.0.0/
// com.ibm.db2z11.doc.java/src/tpc/imjcc_r0052001.dita
mode.supportedClientInfoPropertiesRegEx =
Pattern.compile("ApplicationName|ClientAccountingInformation|" +
"ClientUser|ClientCorrelationToken");
mode.prohibitEmptyInPredicate = true;
add(mode);
mode = new Mode("Derby");
mode.aliasColumnName = true;
mode.uniqueIndexSingleNull = true;
mode.supportOffsetFetch = true;
mode.sysDummy1 = true;
mode.isolationLevelInSelectOrInsertStatement = true;
// Derby does not support client info properties as of version 10.12.1.1
mode.supportedClientInfoPropertiesRegEx = null;
add(mode);
mode = new Mode("HSQLDB");
mode.aliasColumnName = true;
mode.convertOnlyToSmallerScale = true;
mode.nullConcatIsNull = true;
mode.uniqueIndexSingleNull = true;
mode.allowPlusForStringConcat = true;
// HSQLDB does not support client info properties. See
// http://hsqldb.org/doc/apidocs/
// org/hsqldb/jdbc/JDBCConnection.html#
// setClientInfo%28java.lang.String,%20java.lang.String%29
mode.supportedClientInfoPropertiesRegEx = null;
add(mode);
mode = new Mode("MSSQLServer");
mode.aliasColumnName = true;
mode.squareBracketQuotedNames = true;
mode.uniqueIndexSingleNull = true;
mode.allowPlusForStringConcat = true;
mode.swapConvertFunctionParameters = true;
mode.supportPoundSymbolForColumnNames = true;
// MS SQL Server does not support client info properties. See
// https://msdn.microsoft.com/en-Us/library/dd571296%28v=sql.110%29.aspx
mode.supportedClientInfoPropertiesRegEx = null;
add(mode);
mode = new Mode("MySQL");
mode.convertInsertNullToZero = true;
mode.indexDefinitionInCreateTable = true;
mode.lowerCaseIdentifiers = true;
mode.onDuplicateKeyUpdate = true;
// MySQL allows to use any key for client info entries. See
// http://grepcode.com/file/repo1.maven.org/maven2/mysql/
// mysql-connector-java/5.1.24/com/mysql/jdbc/
// JDBC4CommentClientInfoProvider.java
mode.supportedClientInfoPropertiesRegEx =
Pattern.compile(".*");
mode.prohibitEmptyInPredicate = true;
add(mode);
mode = new Mode("Oracle");
mode.aliasColumnName = true;
mode.convertOnlyToSmallerScale = true;
mode.uniqueIndexSingleNullExceptAllColumnsAreNull = true;
mode.treatEmptyStringsAsNull = true;
mode.supportPoundSymbolForColumnNames = true;
// Oracle accepts keys of the form <namespace>.*. See
// https://docs.oracle.com/database/121/JJDBC/jdbcvers.htm#JJDBC29006
mode.supportedClientInfoPropertiesRegEx =
Pattern.compile(".*\\..*");
mode.prohibitEmptyInPredicate = true;
add(mode);
mode = new Mode("PostgreSQL");
mode.aliasColumnName = true;
mode.nullConcatIsNull = true;
mode.supportOffsetFetch = true;
mode.systemColumns = true;
mode.logIsLogBase10 = true;
mode.serialColumnIsNotPK = true;
// PostgreSQL only supports the ApplicationName property. See
// https://github.com/hhru/postgres-jdbc/blob/master/postgresql-jdbc-9.2-1002.src/
// org/postgresql/jdbc4/AbstractJdbc4Connection.java
mode.supportedClientInfoPropertiesRegEx =
Pattern.compile("ApplicationName");
mode.prohibitEmptyInPredicate = true;
add(mode);
}
private Mode(String name) {
this.name = name;
}
private static void add(Mode mode) {
MODES.put(StringUtils.toUpperEnglish(mode.name), mode);
}
/**
* Get the mode with the given name.
*
* @param name the name of the mode
* @return the mode object
*/
public static Mode getInstance(String name) {
return MODES.get(StringUtils.toUpperEnglish(name));
}
public String getName() {
return name;
}
}