Package org.apache.metamodel.jdbc.dialects

Interface IQueryRewriter

All Known Implementing Classes:

AbstractQueryRewriter, DB2QueryRewriter, DefaultQueryRewriter, H2QueryRewriter, Hive2QueryRewriter, HiveQueryRewriter, HsqldbQueryRewriter, ImpalaQueryRewriter, LimitOffsetQueryRewriter, MysqlQueryRewriter, OffsetFetchQueryRewriter, OracleQueryRewriter, PostgresqlQueryRewriter, RowNumberQueryRewriter, SQLiteQueryRewriter, SQLServerQueryRewriter

public interface IQueryRewriter

A query rewriter can be used for rewriting (part of) a query's string representation. This is usefull for databases that deviate from the SQL 99 compliant syntax which is delievered by the query and it's query item's toString() methods.

See Also:

AbstractQueryRewriter, JdbcDataContext

Method Summary

Modifier and Type	Method	Description
String	escapeQuotes(String item)	Escapes the quotes within a String literal of a query item.
org.apache.metamodel.schema.ColumnType	getColumnType(int jdbcType, String nativeType, Integer columnSize)	Gets the column type for a specific JDBC type (as defined in Types), native type name and column size.
Object	getResultSetValue(ResultSet resultSet, int columnIndex, org.apache.metamodel.schema.Column column)	Retrieves a value from a JDBC ResultSet when the anticipated value is mapped to a particular column.
boolean	isAggregateFunctionSupported(org.apache.metamodel.query.AggregateFunction function)	Determines whether a specific aggregate function is supported by the database or not.
boolean	isFirstRowSupported(org.apache.metamodel.query.Query query)	Gets whether this query rewriter is able to write the "First row" query property to the query string.
boolean	isMaxRowsSupported()	Gets whether this query rewriter is able to write the "Max rows" query property to the query string.
boolean	isPrimaryKeySupported()	Determines if the JDBC data source supports primary keys or not.
boolean	isScalarFunctionSupported(org.apache.metamodel.query.ScalarFunction function)	Determines whether a specific scalar function is supported by the database or not.
boolean	isTransactional()	Determines if the JDBC data source supports transactions or not.
String	rewriteColumnType(org.apache.metamodel.schema.ColumnType columnType, Integer columnSize)	Rewrites the name of a column type, as it is written in CREATE TABLE statements.
String	rewriteFilterItem(org.apache.metamodel.query.FilterItem whereItem)
String	rewriteFromItem(org.apache.metamodel.query.FromItem item)
String	rewriteQuery(org.apache.metamodel.query.Query query)
void	setStatementParameter(PreparedStatement st, int valueIndex, org.apache.metamodel.schema.Column column, Object value)	Method which handles the action of setting a parameterized value on a statement.

Method Detail

rewriteFromItem

String rewriteFromItem(org.apache.metamodel.query.FromItem item)

rewriteQuery

String rewriteQuery(org.apache.metamodel.query.Query query)

rewriteFilterItem

String rewriteFilterItem(org.apache.metamodel.query.FilterItem whereItem)

setStatementParameter

void setStatementParameter(PreparedStatement st,
                           int valueIndex,
                           org.apache.metamodel.schema.Column column,
                           Object value)
                    throws SQLException

Method which handles the action of setting a parameterized value on a statement. Traditionally this is done using the PreparedStatement.setObject(int, Object) method but for some types we use more specific setter methods.

Parameters:

st -

valueIndex -

column -

value -

Throws:

SQLException

getResultSetValue

Object getResultSetValue(ResultSet resultSet,
                         int columnIndex,
                         org.apache.metamodel.schema.Column column)
                  throws SQLException

Retrieves a value from a JDBC ResultSet when the anticipated value is mapped to a particular column.

Parameters:

resultSet -

columnIndex -

column -

Returns:

Throws:

SQLException

isMaxRowsSupported

boolean isMaxRowsSupported()

Gets whether this query rewriter is able to write the "Max rows" query property to the query string.

Returns:

whether this query rewriter is able to write the "Max rows" query property to the query string.

isFirstRowSupported

boolean isFirstRowSupported(org.apache.metamodel.query.Query query)

Gets whether this query rewriter is able to write the "First row" query property to the query string.

Parameters:

query - For some database engines, the content of the query decides the ability to change first row

Returns:

whether this query rewriter is able to write the "First row" query property to the query string.

isScalarFunctionSupported

boolean isScalarFunctionSupported(org.apache.metamodel.query.ScalarFunction function)

Determines whether a specific scalar function is supported by the database or not. If the function is not supported then MetaModel will handle the function on the client side.

Parameters:

function -

Returns:

isAggregateFunctionSupported

boolean isAggregateFunctionSupported(org.apache.metamodel.query.AggregateFunction function)

Determines whether a specific aggregate function is supported by the database or not. If the function is not supported then MetaModel will handle the function on the client side.

Parameters:

function -

Returns:

escapeQuotes

String escapeQuotes(String item)

Escapes the quotes within a String literal of a query item.

Returns:

String item with quotes escaped.

rewriteColumnType

String rewriteColumnType(org.apache.metamodel.schema.ColumnType columnType,
                         Integer columnSize)

Rewrites the name of a column type, as it is written in CREATE TABLE statements. Some databases dont support all column types, or have different names for them. The implementation of this method will do that conversion.

Parameters:

columnType - the (non-null) ColumnType to rewrite

columnSize - the (possibly null) column size that may or may not have been specified

Returns:

getColumnType

org.apache.metamodel.schema.ColumnType getColumnType(int jdbcType,
                                                     String nativeType,
                                                     Integer columnSize)

Gets the column type for a specific JDBC type (as defined in Types), native type name and column size.

Parameters:

jdbcType -

nativeType -

columnSize -

Returns:

isTransactional

boolean isTransactional()

Determines if the JDBC data source supports transactions or not. Usually this is the case since JDBC is designed for ACID compliant databases, but in some cases the JDBC interface is used also to facilitate connectivity to non-transactional data source such as Apache Hive and others.

Returns:

isPrimaryKeySupported

boolean isPrimaryKeySupported()

Determines if the JDBC data source supports primary keys or not.

Returns: