All Known Implementing Classes:

DelegatingTypeSystem, RelDataTypeSystemImpl
```
public interface RelDataTypeSystem
```
Type system.
Provides behaviors concerning type limits and behaviors. For example, in the default system, a DECIMAL can have maximum precision 19, but Hive overrides to 38.
The default implementation is DEFAULT.

Field Summary

Fields
Modifier and Type Field Description

static RelDataTypeSystem DEFAULT
Default type system.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`RelDataType`	`deriveAvgAggType(RelDataTypeFactory typeFactory, RelDataType argumentType)`	Returns the return type of a call to the `AVG`, `STDDEV` or `VAR` aggregate functions, inferred from its argument type.
`RelDataType`	`deriveCovarType(RelDataTypeFactory typeFactory, RelDataType arg0Type, RelDataType arg1Type)`	Returns the return type of a call to the `COVAR` aggregate function, inferred from its argument types.
`default RelDataType`	`deriveDecimalDivideType(RelDataTypeFactory typeFactory, RelDataType type1, RelDataType type2)`	Infers the return type of a decimal division.
`default RelDataType`	`deriveDecimalModType(RelDataTypeFactory typeFactory, RelDataType type1, RelDataType type2)`	Infers the return type of a decimal modulus operation.
`default RelDataType`	`deriveDecimalMultiplyType(RelDataTypeFactory typeFactory, RelDataType type1, RelDataType type2)`	Infers the return type of a decimal multiplication.
`default RelDataType`	`deriveDecimalPlusType(RelDataTypeFactory typeFactory, RelDataType type1, RelDataType type2)`	Infers the return type of a decimal addition.
`RelDataType`	`deriveFractionalRankType(RelDataTypeFactory typeFactory)`	Returns the return type of the `CUME_DIST` and `PERCENT_RANK` aggregate functions.
`RelDataType`	`deriveRankType(RelDataTypeFactory typeFactory)`	Returns the return type of the `NTILE`, `RANK`, `DENSE_RANK`, and `ROW_NUMBER` aggregate functions.
`RelDataType`	`deriveSumType(RelDataTypeFactory typeFactory, RelDataType argumentType)`	Returns the return type of a call to the `SUM` aggregate function, inferred from its argument type.
`int`	`getDefaultPrecision(SqlTypeName typeName)`	Returns default precision for this type if supported, otherwise -1 if precision is either unsupported or must be specified explicitly.
`java.lang.String`	`getLiteral(SqlTypeName typeName, boolean isPrefix)`	Returns the LITERAL string for the type, either PREFIX/SUFFIX.
`int`	`getMaxNumericPrecision()`	Returns the maximum precision of a NUMERIC or DECIMAL type.
`int`	`getMaxNumericScale()`	Returns the maximum scale of a NUMERIC or DECIMAL type.
`int`	`getMaxPrecision(SqlTypeName typeName)`	Returns the maximum precision (or length) allowed for this type, or -1 if precision/length are not applicable for this type.
`int`	`getMaxScale(SqlTypeName typeName)`	Returns the maximum scale of a given type.
`int`	`getNumTypeRadix(SqlTypeName typeName)`	Returns the numeric type radix, typically 2 or 10.
`boolean`	`isAutoincrement(SqlTypeName typeName)`	Returns whether the type can be auto increment.
`boolean`	`isCaseSensitive(SqlTypeName typeName)`	Returns whether the type is case sensitive.
`boolean`	`isSchemaCaseSensitive()`	Whether two record types are considered distinct if their field names are the same but in different cases.
`boolean`	`shouldConvertRaggedUnionTypesToVarying()`	Whether the least restrictive type of a number of CHAR types of different lengths should be a VARCHAR type.
`default boolean`	`shouldUseDoubleMultiplication(RelDataTypeFactory typeFactory, RelDataType type1, RelDataType type2)`	Returns whether a decimal multiplication should be implemented by casting arguments to double values.

- Field Detail
  - DEFAULT
```
static final RelDataTypeSystem DEFAULT
```
    Default type system.
- Method Detail
  - getMaxScale
```
int getMaxScale(SqlTypeName typeName)
```
    Returns the maximum scale of a given type.
  - getDefaultPrecision
```
int getDefaultPrecision(SqlTypeName typeName)
```
    Returns default precision for this type if supported, otherwise -1 if precision is either unsupported or must be specified explicitly.
    
    Returns:
    
    Default precision
  - getMaxPrecision
```
int getMaxPrecision(SqlTypeName typeName)
```
    Returns the maximum precision (or length) allowed for this type, or -1 if precision/length are not applicable for this type.
    
    Returns:
    
    Maximum allowed precision
  - getMaxNumericScale
```
int getMaxNumericScale()
```
    Returns the maximum scale of a NUMERIC or DECIMAL type.
  - getMaxNumericPrecision
```
int getMaxNumericPrecision()
```
    Returns the maximum precision of a NUMERIC or DECIMAL type.
  - getLiteral
```
java.lang.String getLiteral(SqlTypeName typeName,
                            boolean isPrefix)
```
    Returns the LITERAL string for the type, either PREFIX/SUFFIX.
  - isCaseSensitive
```
boolean isCaseSensitive(SqlTypeName typeName)
```
    Returns whether the type is case sensitive.
  - isAutoincrement
```
boolean isAutoincrement(SqlTypeName typeName)
```
    Returns whether the type can be auto increment.
  - getNumTypeRadix
```
int getNumTypeRadix(SqlTypeName typeName)
```
    Returns the numeric type radix, typically 2 or 10. 0 means "not applicable".
  - deriveSumType
```
RelDataType deriveSumType(RelDataTypeFactory typeFactory,
                          RelDataType argumentType)
```
    Returns the return type of a call to the SUM aggregate function, inferred from its argument type.
  - deriveAvgAggType
```
RelDataType deriveAvgAggType(RelDataTypeFactory typeFactory,
                             RelDataType argumentType)
```
    Returns the return type of a call to the AVG, STDDEV or VAR aggregate functions, inferred from its argument type.
  - deriveCovarType
```
RelDataType deriveCovarType(RelDataTypeFactory typeFactory,
                            RelDataType arg0Type,
                            RelDataType arg1Type)
```
    Returns the return type of a call to the COVAR aggregate function, inferred from its argument types.
  - deriveFractionalRankType
```
RelDataType deriveFractionalRankType(RelDataTypeFactory typeFactory)
```
    Returns the return type of the CUME_DIST and PERCENT_RANK aggregate functions.
  - deriveRankType
```
RelDataType deriveRankType(RelDataTypeFactory typeFactory)
```
    Returns the return type of the NTILE, RANK, DENSE_RANK, and ROW_NUMBER aggregate functions.
  - isSchemaCaseSensitive
```
boolean isSchemaCaseSensitive()
```
    Whether two record types are considered distinct if their field names are the same but in different cases.
  - shouldConvertRaggedUnionTypesToVarying
```
boolean shouldConvertRaggedUnionTypesToVarying()
```
    Whether the least restrictive type of a number of CHAR types of different lengths should be a VARCHAR type. And similarly BINARY to VARBINARY.
  - deriveDecimalPlusType
```
default RelDataType deriveDecimalPlusType(RelDataTypeFactory typeFactory,
                                          RelDataType type1,
                                          RelDataType type2)
```
    Infers the return type of a decimal addition. Decimal addition involves at least one decimal operand and requires both operands to have exact numeric types.
    Rules:
    
    Let p1, s1 be the precision and scale of the first operand
    
    Let p2, s2 be the precision and scale of the second operand
    
    Let p, s be the precision and scale of the result
    
    Let d be the number of whole digits in the result
    
    Then the result type is a decimal with:
    
    s = max(s1, s2)
    
    p = max(p1 - s1, p2 - s2) + s + 1
    
    p and s are capped at their maximum values
    Parameters:
    
    typeFactory - typeFactory used to create output type
    
    type1 - type of the first operand
    
    type2 - type of the second operand
    
    Returns:
    
    the result type for a decimal addition.
    
    See Also:
    
    SQL:2003 Part 2 Section 6.26
  - shouldUseDoubleMultiplication
```
default boolean shouldUseDoubleMultiplication(RelDataTypeFactory typeFactory,
                                              RelDataType type1,
                                              RelDataType type2)
```
    Returns whether a decimal multiplication should be implemented by casting arguments to double values.
    Pre-condition: createDecimalProduct(type1, type2) != null
  - deriveDecimalMultiplyType
```
default RelDataType deriveDecimalMultiplyType(RelDataTypeFactory typeFactory,
                                              RelDataType type1,
                                              RelDataType type2)
```
    Infers the return type of a decimal multiplication. Decimal multiplication involves at least one decimal operand and requires both operands to have exact numeric types.
    The default implementation is SQL:2003 compliant.
    Rules:
    
    Let p1, s1 be the precision and scale of the first operand
    
    Let p2, s2 be the precision and scale of the second operand
    
    Let p, s be the precision and scale of the result
    
    Let d be the number of whole digits in the result
    
    Then the result type is a decimal with:
    
    p = p1 + p2)
    
    s = s1 + s2
    
    p and s are capped at their maximum values
    
    p and s are capped at their maximum values
    Parameters:
    
    typeFactory - typeFactory used to create output type
    
    type1 - type of the first operand
    
    type2 - type of the second operand
    
    Returns:
    
    the result type for a decimal multiplication, or null if decimal multiplication should not be applied to the operands.
    
    See Also:
    
    SQL:2003 Part 2 Section 6.26
  - deriveDecimalDivideType
```
default RelDataType deriveDecimalDivideType(RelDataTypeFactory typeFactory,
                                            RelDataType type1,
                                            RelDataType type2)
```
    Infers the return type of a decimal division. Decimal division involves at least one decimal operand and requires both operands to have exact numeric types.
    The default implementation is SQL:2003 compliant.
    Rules:
    
    Let p1, s1 be the precision and scale of the first operand
    
    Let p2, s2 be the precision and scale of the second operand
    
    Let p, s be the precision and scale of the result
    
    Let d be the number of whole digits in the result
    
    Then the result type is a decimal with:
    
    d = p1 - s1 + s2
    
    s < max(6, s1 + p2 + 1)
    
    p = d + s
    
    p and s are capped at their maximum values
    Parameters:
    
    typeFactory - typeFactory used to create output type
    
    type1 - type of the first operand
    
    type2 - type of the second operand
    
    Returns:
    
    the result type for a decimal division, or null if decimal division should not be applied to the operands.
    
    See Also:
    
    SQL:2003 Part 2 Section 6.26
  - deriveDecimalModType
```
default RelDataType deriveDecimalModType(RelDataTypeFactory typeFactory,
                                         RelDataType type1,
                                         RelDataType type2)
```
    Infers the return type of a decimal modulus operation. Decimal modulus involves at least one decimal operand and requires both operands to have exact numeric types.
    The default implementation is SQL:2003 compliant: the declared type of the result is the declared type of the second operand (expression divisor).
    
    Parameters:
    
    typeFactory - typeFactory used to create output type
    
    type1 - type of the first operand
    
    type2 - type of the second operand
    
    Returns:
    
    the result type for a decimal modulus, or null if decimal modulus should not be applied to the operands.
    
    See Also:
    
    SQL:2003 Part 2 Section 6.27

Interface RelDataTypeSystem

Field Summary

Method Summary

Field Detail

DEFAULT

Method Detail

getMaxScale

getDefaultPrecision

getMaxPrecision

getMaxNumericScale

getMaxNumericPrecision

getLiteral

isCaseSensitive

isAutoincrement

getNumTypeRadix

deriveSumType

deriveAvgAggType

deriveCovarType

deriveFractionalRankType

deriveRankType

isSchemaCaseSensitive

shouldConvertRaggedUnionTypesToVarying

deriveDecimalPlusType

shouldUseDoubleMultiplication

deriveDecimalMultiplyType

deriveDecimalDivideType

deriveDecimalModType