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/*
* Copyright 2004-2023 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.engine;
import java.sql.Types;
import java.util.Collections;
import java.util.HashMap;
import java.util.Set;
import java.util.regex.Pattern;
import org.h2.util.StringUtils;
import org.h2.value.DataType;
import org.h2.value.Value;
/**
* The compatibility modes. There is a fixed set of modes (for example
* PostgreSQL, MySQL). Each mode has different settings.
*/
public class Mode {
public enum ModeEnum {
REGULAR, STRICT, LEGACY, DB2, Derby, MariaDB, MSSQLServer, HSQLDB, MySQL, Oracle, PostgreSQL
}
/**
* Generation of column names for expressions.
*/
public enum ExpressionNames {
/**
* Use optimized SQL representation of expression.
*/
OPTIMIZED_SQL,
/**
* Use original SQL representation of expression.
*/
ORIGINAL_SQL,
/**
* Generate empty name.
*/
EMPTY,
/**
* Use ordinal number of a column.
*/
NUMBER,
/**
* Use ordinal number of a column with C prefix.
*/
C_NUMBER,
/**
* Use function name for functions and ?column? for other expressions
*/
POSTGRESQL_STYLE,
}
/**
* Generation of column names for expressions to be used in a view.
*/
public enum ViewExpressionNames {
/**
* Use both specified and generated names as is.
*/
AS_IS,
/**
* Throw exception for unspecified names.
*/
EXCEPTION,
/**
* Use both specified and generated names as is, but replace too long
* generated names with {@code Name_exp_###}.
*/
MYSQL_STYLE,
}
/**
* When CHAR values are right-padded with spaces.
*/
public enum CharPadding {
/**
* CHAR values are always right-padded with spaces.
*/
ALWAYS,
/**
* Spaces are trimmed from the right side of CHAR values, but CHAR
* values in result sets are right-padded with spaces to the declared
* length
*/
IN_RESULT_SETS,
/**
* Spaces are trimmed from the right side of CHAR values.
*/
NEVER
}
private static final HashMap 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 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
* INDEX(..) or KEY(..).
* Example: create table test(id int primary key, name varchar(255),
* key idx_name(name));
*/
public boolean indexDefinitionInCreateTable;
/**
* Identifiers may be quoted using square brackets as in [Test].
*/
public boolean squareBracketQuotedNames;
/**
* The system columns 'ctid' and 'oid' are supported.
*/
public boolean systemColumns;
/**
* Determines how rows with {@code NULL} values in indexed columns are handled
* in unique indexes and constraints by default.
*/
public NullsDistinct nullsDistinct = NullsDistinct.DISTINCT;
/**
* Empty strings are treated like NULL values. Useful for Oracle emulation.
*/
public boolean treatEmptyStringsAsNull;
/**
* If {@code true} GREATEST and LEAST ignore nulls
*/
public boolean greatestLeastIgnoreNulls;
/**
* Support the pseudo-table SYSIBM.SYSDUMMY1.
*/
public boolean sysDummy1;
/**
* Text can be concatenated using '+'.
*/
public boolean allowPlusForStringConcat;
/**
* The single-argument function LOG() uses base 10 instead of E.
*/
public boolean logIsLogBase10;
/**
* Swap the parameters of LOG() function.
*/
public boolean swapLogFunctionParameters;
/**
* The function REGEXP_REPLACE() uses \ for back-references.
*/
public boolean regexpReplaceBackslashReferences;
/**
* 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 ... and INSERT IGNORE.
*/
public boolean onDuplicateKeyUpdate;
/**
* MySQL style REPLACE INTO.
*/
public boolean replaceInto;
/**
* PostgreSQL style INSERT ... ON CONFLICT DO NOTHING.
*/
public boolean insertOnConflict;
/**
* Pattern describing the keys the java.sql.Connection.setClientInfo()
* method accepts.
*/
public Pattern supportedClientInfoPropertiesRegEx;
/**
* Support the # for column names
*/
public boolean supportPoundSymbolForColumnNames;
/**
* Whether IN predicate may have an empty value list.
*/
public boolean allowEmptyInPredicate;
/**
* How to pad or trim CHAR values.
*/
public CharPadding charPadding = CharPadding.ALWAYS;
/**
* Whether DB2 TIMESTAMP formats are allowed.
*/
public boolean allowDB2TimestampFormat;
/**
* Discard SQLServer table hints (e.g. "SELECT * FROM table WITH (NOLOCK)")
*/
public boolean discardWithTableHints;
/**
* If {@code true}, datetime value function return the same value within a
* transaction, if {@code false} datetime value functions return the same
* value within a command.
*/
public boolean dateTimeValueWithinTransaction;
/**
* If {@code true} {@code 0x}-prefixed numbers are parsed as binary string
* literals, if {@code false} they are parsed as hexadecimal numeric values.
*/
public boolean zeroExLiteralsAreBinaryStrings;
/**
* If {@code true} unrelated ORDER BY expression are allowed in DISTINCT
* queries, if {@code false} they are disallowed.
*/
public boolean allowUnrelatedOrderByExpressionsInDistinctQueries;
/**
* If {@code true} some additional non-standard ALTER TABLE commands are allowed.
*/
public boolean alterTableExtensionsMySQL;
/**
* If {@code true} non-standard ALTER TABLE MODIFY COLUMN is allowed.
*/
public boolean alterTableModifyColumn;
/**
* If {@code true} non-standard ALTER TABLE MODIFY COLUMN preserves nullability when changing data type.
*/
public boolean alterTableModifyColumnPreserveNullability;
/**
* If {@code true} MySQL table and column options are allowed
*/
public boolean mySqlTableOptions;
/**
* If {@code true} DELETE identifier FROM is allowed
*/
public boolean deleteIdentifierFrom;
/**
* If {@code true} TRUNCATE TABLE uses RESTART IDENTITY by default.
*/
public boolean truncateTableRestartIdentity;
/**
* If {@code true} NEXT VALUE FOR SEQUENCE, CURRENT VALUE FOR SEQUENCE,
* SEQUENCE.NEXTVAL, and SEQUENCE.CURRVAL return values with DECIMAL/NUMERIC
* data type instead of BIGINT.
*/
public boolean decimalSequences;
/**
* If {@code true} constructs like 'CREATE TABLE CATALOG..TABLE_NAME' are allowed,
* the default schema is used.
*/
public boolean allowEmptySchemaValuesAsDefaultSchema;
/**
* If {@code true} all numeric data types may have precision and 'UNSIGNED'
* clause.
*/
public boolean allNumericTypesHavePrecision;
/**
* If {@code true} 'FOR BIT DATA' clauses are allowed for character string
* data types.
*/
public boolean forBitData;
/**
* If {@code true} 'CHAR' and 'BYTE' length units are allowed.
*/
public boolean charAndByteLengthUnits;
/**
* If {@code true}, sequence.NEXTVAL and sequence.CURRVAL pseudo columns are
* supported.
*/
public boolean nextvalAndCurrvalPseudoColumns;
/**
* If {@code true}, the next value expression returns different values when
* invoked multiple times within a row. This setting does not affect
* NEXTVAL() function.
*/
public boolean nextValueReturnsDifferentValues;
/**
* If {@code true}, sequences of generated by default identity columns are
* updated when value is provided by user.
*/
public boolean updateSequenceOnManualIdentityInsertion;
/**
* If {@code true}, last identity of the session is updated on insertion of
* a new value into identity column.
*/
public boolean takeInsertedIdentity;
/**
* If {@code true}, last identity of the session is updated on generation of
* a new sequence value.
*/
public boolean takeGeneratedSequenceValue;
/**
* If {@code true}, identity columns have DEFAULT ON NULL clause.
*/
public boolean identityColumnsHaveDefaultOnNull;
/**
* If {@code true}, merge when matched clause may have WHERE clause.
*/
public boolean mergeWhere;
/**
* If {@code true}, allow using from clause in update statement.
*/
public boolean allowUsingFromClauseInUpdateStatement;
/**
* If {@code true}, referential constraints will create a unique constraint
* on referenced columns if it doesn't exist instead of throwing an
* exception.
*/
public boolean createUniqueConstraintForReferencedColumns;
/**
* How column names are generated for expressions.
*/
public ExpressionNames expressionNames = ExpressionNames.OPTIMIZED_SQL;
/**
* How column names are generated for views.
*/
public ViewExpressionNames viewExpressionNames = ViewExpressionNames.AS_IS;
/**
* Whether TOP clause in SELECT queries is supported.
*/
public boolean topInSelect;
/**
* Whether TOP clause in DML commands is supported.
*/
public boolean topInDML;
/**
* Whether LIMIT / OFFSET clauses are supported.
*/
public boolean limit;
/**
* Whether MINUS can be used as EXCEPT.
*/
public boolean minusIsExcept;
/**
* Whether IDENTITY pseudo data type is supported.
*/
public boolean identityDataType;
/**
* Whether SERIAL and BIGSERIAL pseudo data types are supported.
*/
public boolean serialDataTypes;
/**
* Whether SQL Server-style IDENTITY clause is supported.
*/
public boolean identityClause;
/**
* Whether MySQL-style AUTO_INCREMENT clause is supported.
*/
public boolean autoIncrementClause;
/**
* Whether DATE data type is parsed as TIMESTAMP(0).
*/
public boolean dateIsTimestamp0;
/**
* Whether NUMERIC and DECIMAL/DEC without parameters are parsed as DECFLOAT.
*/
public boolean numericIsDecfloat;
/**
* An optional Set of hidden/disallowed column types.
* Certain DBMSs don't support all column types provided by H2, such as
* "NUMBER" when using PostgreSQL mode.
*/
public Set disallowedTypes = Collections.emptySet();
/**
* Custom mappings from type names to data types.
*/
public HashMap typeByNameMap = new HashMap<>();
/**
* Allow to use GROUP BY n, where n is column index in the SELECT list, similar to ORDER BY
*/
public boolean groupByColumnIndex;
/**
* Allow to compare numeric with BOOLEAN.
*/
public boolean numericWithBooleanComparison;
/**
* Accepts comma ',' as key/value separator in JSON_OBJECT and JSON_OBJECTAGG functions.
*/
public boolean acceptsCommaAsJsonKeyValueSeparator;
private final String name;
private final ModeEnum modeEnum;
static {
Mode mode = new Mode(ModeEnum.REGULAR);
mode.allowEmptyInPredicate = true;
mode.dateTimeValueWithinTransaction = true;
mode.topInSelect = true;
mode.limit = true;
mode.minusIsExcept = true;
mode.identityDataType = true;
mode.serialDataTypes = true;
mode.autoIncrementClause = true;
add(mode);
mode = new Mode(ModeEnum.STRICT);
mode.dateTimeValueWithinTransaction = true;
add(mode);
mode = new Mode(ModeEnum.LEGACY);
// Features of REGULAR mode
mode.allowEmptyInPredicate = true;
mode.dateTimeValueWithinTransaction = true;
mode.topInSelect = true;
mode.limit = true;
mode.minusIsExcept = true;
mode.identityDataType = true;
mode.serialDataTypes = true;
mode.autoIncrementClause = true;
// Legacy identity and sequence features
mode.identityClause = true;
mode.updateSequenceOnManualIdentityInsertion = true;
mode.takeInsertedIdentity = true;
mode.identityColumnsHaveDefaultOnNull = true;
mode.nextvalAndCurrvalPseudoColumns = true;
// Legacy DML features
mode.topInDML = true;
mode.mergeWhere = true;
// Legacy DDL features
mode.createUniqueConstraintForReferencedColumns = true;
// Legacy numeric with boolean comparison
mode.numericWithBooleanComparison = true;
// Legacy GREATEST and LEAST null treatment
mode.greatestLeastIgnoreNulls = true;
add(mode);
mode = new Mode(ModeEnum.DB2);
mode.aliasColumnName = 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.allowDB2TimestampFormat = true;
mode.forBitData = true;
mode.takeInsertedIdentity = true;
mode.nextvalAndCurrvalPseudoColumns = true;
mode.expressionNames = ExpressionNames.NUMBER;
mode.viewExpressionNames = ViewExpressionNames.EXCEPTION;
mode.limit = true;
mode.minusIsExcept = true;
mode.numericWithBooleanComparison = true;
add(mode);
mode = new Mode(ModeEnum.Derby);
mode.aliasColumnName = true;
mode.nullsDistinct = NullsDistinct.NOT_DISTINCT;
mode.sysDummy1 = true;
mode.isolationLevelInSelectOrInsertStatement = true;
// Derby does not support client info properties as of version 10.12.1.1
mode.supportedClientInfoPropertiesRegEx = null;
mode.forBitData = true;
mode.takeInsertedIdentity = true;
mode.expressionNames = ExpressionNames.NUMBER;
mode.viewExpressionNames = ViewExpressionNames.EXCEPTION;
add(mode);
mode = new Mode(ModeEnum.HSQLDB);
mode.allowPlusForStringConcat = true;
mode.identityColumnsHaveDefaultOnNull = true;
// HSQLDB does not support client info properties. See
// http://hsqldb.org/doc/apidocs/org/hsqldb/jdbc/JDBCConnection.html#setClientInfo-java.lang.String-java.lang.String-
mode.supportedClientInfoPropertiesRegEx = null;
mode.expressionNames = ExpressionNames.C_NUMBER;
mode.topInSelect = true;
mode.limit = true;
mode.minusIsExcept = true;
mode.numericWithBooleanComparison = true;
add(mode);
mode = new Mode(ModeEnum.MSSQLServer);
mode.aliasColumnName = true;
mode.squareBracketQuotedNames = true;
mode.nullsDistinct = NullsDistinct.NOT_DISTINCT;
mode.greatestLeastIgnoreNulls = true;
mode.allowPlusForStringConcat = true;
mode.swapLogFunctionParameters = true;
mode.swapConvertFunctionParameters = true;
mode.supportPoundSymbolForColumnNames = true;
mode.discardWithTableHints = 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;
mode.zeroExLiteralsAreBinaryStrings = true;
mode.truncateTableRestartIdentity = true;
mode.takeInsertedIdentity = true;
DataType dt = DataType.createNumeric(19, 4);
dt.type = Value.NUMERIC;
dt.sqlType = Types.NUMERIC;
dt.specialPrecisionScale = true;
mode.typeByNameMap.put("MONEY", dt);
dt = DataType.createNumeric(10, 4);
dt.type = Value.NUMERIC;
dt.sqlType = Types.NUMERIC;
dt.specialPrecisionScale = true;
mode.typeByNameMap.put("SMALLMONEY", dt);
mode.typeByNameMap.put("UNIQUEIDENTIFIER", DataType.getDataType(Value.UUID));
mode.allowEmptySchemaValuesAsDefaultSchema = true;
mode.expressionNames = ExpressionNames.EMPTY;
mode.viewExpressionNames = ViewExpressionNames.EXCEPTION;
mode.topInSelect = true;
mode.topInDML = true;
mode.identityClause = true;
mode.numericWithBooleanComparison = true;
add(mode);
mode = new Mode(ModeEnum.MariaDB);
mode.indexDefinitionInCreateTable = true;
mode.regexpReplaceBackslashReferences = true;
mode.onDuplicateKeyUpdate = true;
mode.replaceInto = true;
mode.charPadding = CharPadding.NEVER;
mode.supportedClientInfoPropertiesRegEx = Pattern.compile(".*");
mode.zeroExLiteralsAreBinaryStrings = true;
mode.allowUnrelatedOrderByExpressionsInDistinctQueries = true;
mode.alterTableExtensionsMySQL = true;
mode.alterTableModifyColumn = true;
mode.mySqlTableOptions = true;
mode.deleteIdentifierFrom = true;
mode.truncateTableRestartIdentity = true;
mode.allNumericTypesHavePrecision = true;
mode.nextValueReturnsDifferentValues = true;
mode.updateSequenceOnManualIdentityInsertion = true;
mode.takeInsertedIdentity = true;
mode.identityColumnsHaveDefaultOnNull = true;
mode.expressionNames = ExpressionNames.ORIGINAL_SQL;
mode.viewExpressionNames = ViewExpressionNames.MYSQL_STYLE;
mode.limit = true;
mode.autoIncrementClause = true;
mode.typeByNameMap.put("YEAR", DataType.getDataType(Value.SMALLINT));
mode.groupByColumnIndex = true;
mode.numericWithBooleanComparison = true;
mode.acceptsCommaAsJsonKeyValueSeparator = true;
add(mode);
mode = new Mode(ModeEnum.MySQL);
mode.indexDefinitionInCreateTable = true;
mode.regexpReplaceBackslashReferences = true;
mode.onDuplicateKeyUpdate = true;
mode.replaceInto = true;
mode.charPadding = CharPadding.NEVER;
// MySQL allows to use any key for client info entries. See
// https://github.com/mysql/mysql-connector-j/blob/5.1.47/src/com/mysql/jdbc/JDBC4CommentClientInfoProvider.java
mode.supportedClientInfoPropertiesRegEx =
Pattern.compile(".*");
mode.zeroExLiteralsAreBinaryStrings = true;
mode.allowUnrelatedOrderByExpressionsInDistinctQueries = true;
mode.alterTableExtensionsMySQL = true;
mode.alterTableModifyColumn = true;
mode.mySqlTableOptions = true;
mode.deleteIdentifierFrom = true;
mode.truncateTableRestartIdentity = true;
mode.allNumericTypesHavePrecision = true;
mode.updateSequenceOnManualIdentityInsertion = true;
mode.takeInsertedIdentity = true;
mode.identityColumnsHaveDefaultOnNull = true;
mode.createUniqueConstraintForReferencedColumns = true;
mode.expressionNames = ExpressionNames.ORIGINAL_SQL;
mode.viewExpressionNames = ViewExpressionNames.MYSQL_STYLE;
mode.limit = true;
mode.autoIncrementClause = true;
mode.typeByNameMap.put("YEAR", DataType.getDataType(Value.SMALLINT));
mode.groupByColumnIndex = true;
mode.numericWithBooleanComparison = true;
mode.acceptsCommaAsJsonKeyValueSeparator = true;
add(mode);
mode = new Mode(ModeEnum.Oracle);
mode.aliasColumnName = true;
mode.convertOnlyToSmallerScale = true;
mode.nullsDistinct = NullsDistinct.ALL_DISTINCT;
mode.treatEmptyStringsAsNull = true;
mode.regexpReplaceBackslashReferences = true;
mode.supportPoundSymbolForColumnNames = true;
// Oracle accepts keys of the form .*. See
// https://docs.oracle.com/database/121/JJDBC/jdbcvers.htm#JJDBC29006
mode.supportedClientInfoPropertiesRegEx =
Pattern.compile(".*\\..*");
mode.alterTableModifyColumn = true;
mode.alterTableModifyColumnPreserveNullability = true;
mode.decimalSequences = true;
mode.charAndByteLengthUnits = true;
mode.nextvalAndCurrvalPseudoColumns = true;
mode.mergeWhere = true;
mode.minusIsExcept = true;
mode.expressionNames = ExpressionNames.ORIGINAL_SQL;
mode.viewExpressionNames = ViewExpressionNames.EXCEPTION;
mode.dateIsTimestamp0 = true;
mode.typeByNameMap.put("BINARY_FLOAT", DataType.getDataType(Value.REAL));
mode.typeByNameMap.put("BINARY_DOUBLE", DataType.getDataType(Value.DOUBLE));
add(mode);
mode = new Mode(ModeEnum.PostgreSQL);
mode.aliasColumnName = true;
mode.systemColumns = true;
mode.greatestLeastIgnoreNulls = true;
mode.logIsLogBase10 = true;
mode.regexpReplaceBackslashReferences = true;
mode.insertOnConflict = 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.charPadding = CharPadding.IN_RESULT_SETS;
mode.nextValueReturnsDifferentValues = true;
mode.takeGeneratedSequenceValue = true;
mode.expressionNames = ExpressionNames.POSTGRESQL_STYLE;
mode.allowUsingFromClauseInUpdateStatement = true;
mode.limit = true;
mode.serialDataTypes = true;
mode.numericIsDecfloat = true;
// Enumerate all H2 types NOT supported by PostgreSQL:
Set disallowedTypes = new java.util.HashSet<>();
disallowedTypes.add("NUMBER");
disallowedTypes.add("TINYINT");
disallowedTypes.add("BLOB");
disallowedTypes.add("VARCHAR_IGNORECASE");
mode.disallowedTypes = disallowedTypes;
dt = DataType.getDataType(Value.JSON);
mode.typeByNameMap.put("JSONB", dt);
dt = DataType.createNumeric(19, 2);
dt.type = Value.NUMERIC;
dt.sqlType = Types.NUMERIC;
dt.specialPrecisionScale = true;
mode.typeByNameMap.put("MONEY", dt);
dt = DataType.getDataType(Value.INTEGER);
mode.typeByNameMap.put("OID", dt);
mode.dateTimeValueWithinTransaction = true;
mode.groupByColumnIndex = true;
add(mode);
}
private Mode(ModeEnum modeEnum) {
this.name = modeEnum.name();
this.modeEnum = modeEnum;
}
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 static Mode getRegular() {
return getInstance(ModeEnum.REGULAR.name());
}
public String getName() {
return name;
}
public ModeEnum getEnum() {
return this.modeEnum;
}
@Override
public String toString() {
return name;
}
}