ModeThe compatibility modes. There is a fixed set of modes (for example PostgreSQL, MySQL). Each mode has different settings.
aliasColumnNameWhen 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.
allowPlusForStringConcatText can be concatenated using '+'.
convertInsertNullToZeroWhen 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.
convertOnlyToSmallerScaleWhen 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.
indexDefinitionInCreateTableCreating 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)); isolationLevelInSelectOrInsertStatementcan set the isolation level using WITH {RR|RS|CS|UR}
logIsLogBase10The function LOG() uses base 10 instead of E.
lowerCaseIdentifiersMeta data calls return identifiers in lower case.
nullConcatIsNullConcatenation 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.
onDuplicateKeyUpdateMySQL style INSERT ... ON DUPLICATE KEY UPDATE ...
serialColumnIsNotPKSERIAL and BIGSERIAL columns are not automatically primary keys.
squareBracketQuotedNamesIdentifiers may be quoted using square brackets as in [Test].
supportOffsetFetchSupport for the syntax
[OFFSET .. ROW|ROWS] [FETCH FIRST .. ROW|ROWS ONLY]
as an alternative for LIMIT .. OFFSET.
swapConvertFunctionParametersSwap the parameters of the CONVERT function.
sysDummy1Support the pseudo-table SYSIBM.SYSDUMMY1.
systemColumnsThe system columns 'CTID' and 'OID' are supported.
treatEmptyStringsAsNullEmpty strings are treated like NULL values. Useful for Oracle emulation.
uniqueIndexSingleNullFor unique indexes, NULL is distinct. That means only one row with NULL
in one of the columns is allowed.
uniqueIndexSingleNullExceptAllColumnsAreNullWhen 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.
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