adql.translator

Class JDBCTranslator

java.lang.Object

adql.translator.JDBCTranslator

All Implemented Interfaces:

ADQLTranslator

Direct Known Subclasses:

MySQLTranslator, PostgreSQLTranslator, SQLServerTranslator

public abstract class JDBCTranslator
extends java.lang.Object
implements ADQLTranslator

Implementation of ADQLTranslator which translates ADQL queries in SQL queries.

It is already able to translate all SQL standard features, but lets abstract the translation of all geometrical functions. So, this translator must be extended as PostgreSQLTranslator, PgSphereTranslator, MySQLTranslator and SQLServerTranslator are doing.

Note: Its default implementation of the SQL syntax has been inspired by the PostgreSQL one. However, it should work also with other DBMS, although some translations might be needed (as it is has been done for PostgreSQL about the mathematical functions).

SQL with or without case sensitivity?

In ADQL and in SQL, it is possible to tell the parser to respect the exact case or not of an identifier (schema, table or column name) by surrounding it with double quotes. However ADQL identifiers and SQL ones may be different. In that way, the case sensitivity specified in ADQL on the different identifiers can not be kept in SQL. That's why this translator lets specify a general rule on which types of SQL identifier must be double quoted. This can be done by implementing the abstract function isCaseSensitive(IdentifierField). The functions translating column and table names will call this function in order to surround the identifiers by double quotes or not. So, be careful if you want to override the functions translating columns and tables!

Translation of "SELECT TOP"

The default behavior of this translator is to translate the ADQL "TOP" into the SQL "LIMIT" at the end of the query. This is ok for some DBMS, but not all. So, if your DBMS does not know the "LIMIT" keyword, you should override the function translating the whole query: translate(ADQLQuery). Here is its current implementation:

        StringBuffer sql = new StringBuffer(translate(query.getSelect()));
        sql.append("\nFROM ").append(translate(query.getFrom()));
        if (!query.getWhere().isEmpty())
                sql.append('\n').append(translate(query.getWhere()));
        if (!query.getGroupBy().isEmpty())
                sql.append('\n').append(translate(query.getGroupBy()));
        if (!query.getHaving().isEmpty())
                sql.append('\n').append(translate(query.getHaving()));
        if (!query.getOrderBy().isEmpty())
                sql.append('\n').append(translate(query.getOrderBy()));
        if (query.getSelect().hasLimit())
                sql.append("\nLimit ").append(query.getSelect().getLimit());
        return sql.toString();
 

Translation of ADQL functions

All ADQL functions are by default not translated. Consequently, the SQL translation is actually the ADQL expression. Generally the ADQL expression is generic enough. However some mathematical functions may need to be translated differently. For instance PostgreSQLTranslator is translating differently: LOG, LOG10, RAND and TRUNC.

Note: Geometrical regions and types have not been managed here. They stay abstract because it is obviously impossible to have a generic translation and conversion ; it totally depends from the database system.

Translation of "FROM" with JOINs

The FROM clause is translated into SQL as written in ADQL. There is no differences except the identifiers that are replaced. The tables' aliases and their case sensitivity are kept like in ADQL.

Since:

1.4

Version:

1.5 (03/2019)

Author:

Grégory Mantelet (ARI;CDS)

See Also:

PostgreSQLTranslator, PgSphereTranslator, MySQLTranslator, SQLServerTranslator

Constructor Summary

Constructors

Constructor and Description
JDBCTranslator()

Method Summary

Modifier and Type	Method and Description
java.lang.StringBuffer	appendIdentifier(java.lang.StringBuffer str, java.lang.String id, boolean caseSensitive) Appends the given identifier to the given StringBuffer.
java.lang.StringBuffer	appendIdentifier(java.lang.StringBuffer str, java.lang.String id, IdentifierField field) Appends the given identifier in the given StringBuffer.
abstract DBType	convertTypeFromDB(int dbmsType, java.lang.String rawDbmsTypeName, java.lang.String dbmsTypeName, java.lang.String[] typeParams) Convert any type provided by a JDBC driver into a type understandable by the ADQL/TAP library.
abstract java.lang.String	convertTypeToDB(DBType type) Convert any type provided by the ADQL/TAP library into a type understandable by a JDBC driver.
java.lang.String	getColumnName(DBColumn column) Get the DB name of the given column
protected java.lang.String	getDefaultADQLFunction(ADQLFunction fct) Gets the default SQL output for the given ADQL function.
protected java.lang.String	getDefaultADQLList(ADQLList<? extends ADQLObject> list) Gets the default SQL output for a list of ADQL objects.
protected java.lang.String	getDefaultADQLList(ADQLList<? extends ADQLObject> list, boolean withNamePrefix) Gets the default SQL output for a list of ADQL objects.
protected java.lang.String	getDefaultColumnReference(ColumnReference ref) Gets the default SQL output for a column reference.
java.lang.String	getQualifiedSchemaName(DBTable table) Get the qualified DB name of the schema containing the given table.
java.lang.String	getQualifiedTableName(DBTable table) Get the qualified DB name of the given table.
java.lang.String	getTableName(DBTable table, boolean withSchema) Get the DB name of the given table.
abstract boolean	isCaseSensitive(IdentifierField field) Tell whether the specified identifier MUST be translated so that being interpreted case sensitively or not.
java.lang.String	translate(ADQLColumn column)
java.lang.String	translate(ADQLConstraint cons)
java.lang.String	translate(ADQLFunction fct)
java.lang.String	translate(ADQLJoin join)
java.lang.String	translate(ADQLList<? extends ADQLObject> list)
java.lang.String	translate(ADQLObject obj)
java.lang.String	translate(ADQLOperand op)
java.lang.String	translate(ADQLOrder order)
java.lang.String	translate(ADQLQuery query)
java.lang.String	translate(ADQLTable table)
java.lang.String	translate(Between comp)
java.lang.String	translate(ClauseConstraints clause)
java.lang.String	translate(ClauseSelect clause)
java.lang.String	translate(ColumnReference ref)
java.lang.String	translate(Comparison comp)
java.lang.String	translate(Concatenation concat)
java.lang.String	translate(Exists exists)
java.lang.String	translate(FromContent content)
java.lang.String	translate(GeometryFunction.GeometryValue<? extends GeometryFunction> geomValue)
java.lang.String	translate(GeometryFunction fct)
java.lang.String	translate(In in)
java.lang.String	translate(IsNull isNull)
java.lang.String	translate(MathFunction fct)
java.lang.String	translate(NegativeOperand negOp)
java.lang.String	translate(NotConstraint notCons)
java.lang.String	translate(NumericConstant numConst)
java.lang.String	translate(Operation op)
java.lang.String	translate(SelectAllColumns item)
java.lang.String	translate(SelectItem item)
java.lang.String	translate(SQLFunction fct)
java.lang.String	translate(StringConstant strConst)
java.lang.String	translate(UserDefinedFunction fct)
java.lang.String	translate(WrappedOperand op)
abstract STCS.Region	translateGeometryFromDB(java.lang.Object jdbcColValue) Parse the given JDBC column value as a geometry object and convert it into a STCS.Region.
abstract java.lang.Object	translateGeometryToDB(STCS.Region region) Convert the given STC region into a DB column value.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface adql.translator.ADQLTranslator

translate, translate, translate, translate, translate, translate, translate, translate, translate, translate, translate, translate

Constructor Detail

JDBCTranslator

public JDBCTranslator()

Method Detail

isCaseSensitive

public abstract boolean isCaseSensitive(IdentifierField field)

Tell whether the specified identifier MUST be translated so that being interpreted case sensitively or not. By default, an identifier that must be translated with case sensitivity will be surrounded by double quotes. But, if this function returns FALSE, the SQL name will be written just as given in the metadata, without double quotes.

WARNING: An IdentifierField object can be a SCHEMA, TABLE, COLUMN and ALIAS. However, in this translator, aliases are translated like in ADQL (so, with the same case sensitivity specification as in ADQL). So, this function will never be used to know the case sensitivity to apply to an alias. It is then useless to write a special behavior for the ALIAS value.

Parameters:

field - The identifier whose the case sensitive to apply is asked.

Returns:

true if the specified identifier must be translated case sensitivity, false otherwise (included if ALIAS or NULL).

getQualifiedSchemaName

public java.lang.String getQualifiedSchemaName(DBTable table)

Get the qualified DB name of the schema containing the given table.

Note: This function will, by default, add double quotes if the schema name must be case sensitive in the SQL query. This information is provided by isCaseSensitive(IdentifierField).

Parameters:

table - A table of the schema whose the qualified DB name is asked.

Returns:

The qualified (with DB catalog name prefix if any, and with double quotes if needed) DB schema name, or an empty string if there is no schema or no DB name.

getQualifiedTableName

public java.lang.String getQualifiedTableName(DBTable table)

Get the qualified DB name of the given table.

Note: This function will, by default, add double quotes if the table name must be case sensitive in the SQL query. This information is provided by isCaseSensitive(IdentifierField).

Parameters:

table - The table whose the qualified DB name is asked.

Returns:

The qualified (with DB catalog and schema prefix if any, and with double quotes if needed) DB table name, or an empty string if the given table is NULL or if there is no DB name.

See Also:

getTableName(DBTable, boolean)

getTableName

public java.lang.String getTableName(DBTable table,
                                     boolean withSchema)

Get the DB name of the given table. The second parameter lets specify whether the table name must be prefixed by the qualified schema name or not.

Note: This function will, by default, add double quotes if the table name must be case sensitive in the SQL query. This information is provided by isCaseSensitive(IdentifierField).

Parameters:

table - The table whose the DB name is asked.

withSchema - true if the qualified schema name must prefix the table name, false otherwise.

Returns:

The DB table name (prefixed by the qualified schema name if asked, and with double quotes if needed), or an empty string if the given table is NULL or if there is no DB name.

Since:

2.0

getColumnName

public java.lang.String getColumnName(DBColumn column)

Get the DB name of the given column

Note: This function will, by default, add double quotes if the column name must be case sensitive in the SQL query. This information is provided by isCaseSensitive(IdentifierField).

Caution: The given column may be NULL and in this case an empty string will be returned. But if the given column is not NULL, its DB name MUST NOT BE NULL!

Parameters:

column - The column whose the DB name is asked.

Returns:

The DB column name (with double quotes if needed), or an empty string if the given column is NULL.

appendIdentifier

public final java.lang.StringBuffer appendIdentifier(java.lang.StringBuffer str,
                                                     java.lang.String id,
                                                     IdentifierField field)

Appends the given identifier in the given StringBuffer.

This function just call appendIdentifier(StringBuffer, String, boolean) with the same 2 first parameters. The third one is the result of: isCaseSensitive(field).

Note: In order to keep a consistent output of the appendIdentifier(...) functions, this function can not be overwritten ; it is just a shortcut function.

Parameters:

str - The string buffer.

id - The identifier to append.

field - The type of identifier (column, table, schema, catalog or alias ?).

Returns:

The string buffer + identifier.

See Also:

appendIdentifier(StringBuffer, String, boolean)

appendIdentifier

public java.lang.StringBuffer appendIdentifier(java.lang.StringBuffer str,
                                               java.lang.String id,
                                               boolean caseSensitive)

Appends the given identifier to the given StringBuffer.

Parameters:

str - The string buffer.

id - The identifier to append.

caseSensitive - true to format the identifier so that preserving the case sensitivity, false otherwise.

Returns:

The string buffer + identifier.

translate

public java.lang.String translate(ADQLObject obj)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(ADQLQuery query)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(ADQLList<? extends ADQLObject> list)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

getDefaultADQLList

protected final java.lang.String getDefaultADQLList(ADQLList<? extends ADQLObject> list)
                                             throws TranslationException

Gets the default SQL output for a list of ADQL objects.

Implementation note: This function just calls getDefaultADQLList(ADQLList, boolean) with the given list in first parameter and true in second one. In other words, this function always prefixes the list items by the list name.

Parameters:

list - List to format into SQL.

Returns:

The corresponding SQL.

Throws:

TranslationException - If there is an error during the translation.

See Also:

getDefaultADQLList(ADQLList, boolean)

getDefaultADQLList

protected java.lang.String getDefaultADQLList(ADQLList<? extends ADQLObject> list,
                                              boolean withNamePrefix)
                                       throws TranslationException

Gets the default SQL output for a list of ADQL objects.

Parameters:

list - List to format into SQL.

withNamePrefix - Prefix the list by its name or not. (e.g. 'false' for a Concatenation)

Returns:

The corresponding SQL.

Throws:

TranslationException - If there is an error during the translation.

Since:

1.4

translate

public java.lang.String translate(ClauseSelect clause)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(ClauseConstraints clause)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(SelectItem item)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(SelectAllColumns item)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(ColumnReference ref)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

getDefaultColumnReference

protected java.lang.String getDefaultColumnReference(ColumnReference ref)
                                              throws TranslationException

Gets the default SQL output for a column reference.

Parameters:

ref - The column reference to format into SQL.

Returns:

The corresponding SQL.

Throws:

TranslationException - If there is an error during the translation.

translate

public java.lang.String translate(ADQLOrder order)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(FromContent content)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(ADQLTable table)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(ADQLJoin join)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(ADQLOperand op)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(ADQLColumn column)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(Concatenation concat)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(NegativeOperand negOp)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(NumericConstant numConst)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(StringConstant strConst)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(WrappedOperand op)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(Operation op)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(ADQLConstraint cons)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(Comparison comp)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(Between comp)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(Exists exists)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(In in)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(IsNull isNull)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(NotConstraint notCons)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(ADQLFunction fct)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

getDefaultADQLFunction

protected final java.lang.String getDefaultADQLFunction(ADQLFunction fct)
                                                 throws TranslationException

Gets the default SQL output for the given ADQL function.

Parameters:

fct - The ADQL function to format into SQL.

Returns:

The corresponding SQL.

Throws:

TranslationException - If there is an error during the translation.

translate

public java.lang.String translate(SQLFunction fct)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(MathFunction fct)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(UserDefinedFunction fct)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(GeometryFunction fct)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

translate

public java.lang.String translate(GeometryFunction.GeometryValue<? extends GeometryFunction> geomValue)
                           throws TranslationException

Specified by:

translate in interface ADQLTranslator

Throws:

TranslationException

convertTypeFromDB

public abstract DBType convertTypeFromDB(int dbmsType,
                                         java.lang.String rawDbmsTypeName,
                                         java.lang.String dbmsTypeName,
                                         java.lang.String[] typeParams)

Convert any type provided by a JDBC driver into a type understandable by the ADQL/TAP library.

Parameters:

dbmsType - Type returned by a JDBC driver. Note: this value is returned by ResultSetMetadata.getColumnType(int) and correspond to a type of java.sql.Types

rawDbmsTypeName - Full name of the type returned by a JDBC driver. Note: this name is returned by ResultSetMetadata.getColumnTypeName(int) ; this name may contain parameters

dbmsTypeName - Name of type, without the eventual parameters. Note: this name is extracted from rawDbmsTypeName.

typeParams - The eventual type parameters (e.g. char string length). Note: these parameters are extracted from rawDbmsTypeName.

Returns:

The corresponding ADQL/TAP type or NULL if the specified type is unknown.

convertTypeToDB

public abstract java.lang.String convertTypeToDB(DBType type)

Convert any type provided by the ADQL/TAP library into a type understandable by a JDBC driver.

Note: The returned DBMS type may contain some parameters between brackets.

Parameters:

type - The ADQL/TAP library's type to convert.

Returns:

The corresponding DBMS type or NULL if the specified type is unknown.

translateGeometryFromDB

public abstract STCS.Region translateGeometryFromDB(java.lang.Object jdbcColValue)
                                             throws ParseException

Parse the given JDBC column value as a geometry object and convert it into a STCS.Region.

Note: Generally the returned object will be used to get its STC-S expression.

Note: If the given column value is NULL, NULL will be returned.

Important note: This function is called ONLY for value of columns flagged as geometries by convertTypeFromDB(int, String, String, String[]). So the value should always be of the expected type and format. However, if it turns out that the type is wrong and that the conversion is finally impossible, this function SHOULD throw a ParseException.

Parameters:

jdbcColValue - A JDBC column value (returned by ResultSet.getObject(int)).

Returns:

The corresponding STCS.Region if the given value is a geometry.

Throws:

ParseException - If the given object is not a geometrical object or can not be transformed into a STCS.Region object.

translateGeometryToDB

public abstract java.lang.Object translateGeometryToDB(STCS.Region region)
                                                throws ParseException

Convert the given STC region into a DB column value.

Note: This function is used only by the UPLOAD feature, to import geometries provided as STC-S expression in a VOTable document inside a DB column.

Note: If the given region is NULL, NULL will be returned.

Parameters:

region - The region to store in the DB.

Returns:

The corresponding DB column object.

Throws:

ParseException - If the given STC Region can not be converted into a DB object.