Backend (Tentackle SQL 2.1.0 API)

All Known Implementing Classes:

AbstractBackend, AbstractSql2003Backend, AbstractSql2008Backend, AbstractSql92Backend, Db2, Informix, Ingres, MsSql, MySql, Oracle, Postgres
```
public interface Backend
```
A database backend.
Defines the backend specifics.
There is only one instance per database type.
Implementations must not maintain any state except for the whole of all connections to the specific kind of database.

Author:

harald

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`SQL_ALLSTAR` '*' all string.
`static String`	`SQL_AND` AND string.
`static String`	`SQL_ANDNOT` AND NOT string.
`static String`	`SQL_COMMA` comma separator.
`static String`	`SQL_COMMA_PAR` Parameter ,? string.
`static String`	`SQL_DELETE` DELETE string.
`static String`	`SQL_EQUAL` = operator string.
`static String`	`SQL_EQUAL_PAR` Parameter =? string.
`static String`	`SQL_EQUAL_PAR_COMMA` Parameter =?, string.
`static String`	`SQL_EQUAL_ZERO` =0 string.
`static String`	`SQL_EXISTS` SQL EXISTS clause with SELECT 1 and opening left parenthesis.
`static String`	`SQL_FROM` FROM string.
`static String`	`SQL_GREATER` > operator string.
`static String`	`SQL_GREATER_PAR` Parameter >? string.
`static String`	`SQL_GREATEROREQUAL` >= operator string.
`static String`	`SQL_GREATEROREQUAL_PAR` Parameter ≥? string.
`static String`	`SQL_GROUPBY` GROUP BY string.
`static String`	`SQL_INSERT_INTO` INSERT INTO string.
`static String`	`SQL_INSERT_VALUES` (VALUES) string for insert.
`static String`	`SQL_ISNOTNULL` IS NOT NULL string.
`static String`	`SQL_ISNULL` IS NULL string.
`static String`	`SQL_LEFT_PARENTHESIS` opening bracket.
`static String`	`SQL_LESS` < operator string.
`static String`	`SQL_LESS_PAR` Parameter <? string.
`static String`	`SQL_LESSOREQUAL` <= operator string.
`static String`	`SQL_LESSOREQUAL_PAR` Parameter <=? string.
`static String`	`SQL_LIKE` LIKE operator string.
`static String`	`SQL_LIKE_PAR` Parameter LIKE ? string.
`static String`	`SQL_MAX` MAX function name.
`static String`	`SQL_MIN` MAX function name.
`static String`	`SQL_NOT` NOT string.
`static String`	`SQL_NOTEQUAL` <> operator string.
`static String`	`SQL_NOTEQUAL_PAR` Parameter <>? string.
`static String`	`SQL_NOTEQUAL_ZERO` <>0 string.
`static String`	`SQL_NOTLIKE` NOT LIKE operator string.
`static String`	`SQL_NOTLIKE_PAR` Parameter NOT LIKE ? string.
`static String`	`SQL_OR` OR string.
`static String`	`SQL_ORDERBY` ORDER BY string.
`static String`	`SQL_ORNOT` OR NOT string.
`static String`	`SQL_PAR` ? string.
`static String`	`SQL_PAR_COMMA` Parameter ?, string.
`static String`	`SQL_PLUS_ONE` +1 string.
`static String`	`SQL_RIGHT_PARENTHESIS` closing bracket.
`static String`	`SQL_SELECT` SELECT string.
`static String`	`SQL_SELECT_ALL_FROM` SELECT * FROM string.
`static String`	`SQL_SET` SET string.
`static String`	`SQL_SORTASC` sort ASC string.
`static String`	`SQL_SORTDESC` sort DESC string.
`static String`	`SQL_UPDATE` UPDATE string.
`static String`	`SQL_WHERE` WHERE string.
`static String`	`SQL_WHEREALL` "WHERE 1=1" allows AND to be added.
`static String`	`SQL_WHEREAND` SQL_WHEREALL + AND will be replaced by...
`static String`	`SQL_WHERENOTHING` "WHERE 1=0" to select nothing.
`static String`	`SQL_WHEREOR` SQL_WHEREALL + OR will be replaced by...

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`boolean`	`allowsExpressionsReferringToTablesBeingUpdated()` Determines whether backend allows expressions referring to tables being updated.
`void`	`assertValidName(String nameType, String name)` Asserts that given string is a valid name and usage.
`String`	`buildSelectSql(String sql, boolean writeLock, int limit, int offset)` Creates a select statement string from an inner sql string.
`void`	`buildSelectSql(StringBuilder sqlBuilder, boolean writeLock, int limit, int offset)` Creates a select statement string from an inner sql string.
`String`	`columnTypeNullDefaultToString(String columnName, SqlType sqlType, int size, int scale, boolean nullable, Object defaultValue)` Converts an sqltype, size, scale, nullable and default value to a database type declaration.
`String`	`columnTypeToString(SqlType sqlType, int size, int scale)` Converts an sqltype, size and scale to a database type declaration.
`ColumnMetaData`	`createColumnMetaData(TableMetaData tableMetaData)` Creates a column meta data instance.
`Connection`	`createConnection(String url, String username, char[] password)` Creates a jdbc connection.
`IndexColumnMetaData`	`createIndexColumnMetaData(IndexMetaData indexMetaData)` Creates an index column meta data instance.
`IndexMetaData`	`createIndexMetaData(TableMetaData tableMetaData)` Creates an index meta data instance.
`TableMetaData`	`createTableMetaData(ModelMetaData metaData, String tableName)` Creates a meta data instance.
`String`	`getBackendId(Connection connection)` Determines the unique id or name used by the backend for a given connection.
`String`	`getCoalesceKeyword()` Gets the keyword for the COALESCE function.
`String`	`getDefaultSchema()` Gets the default schema name. Some backends store the objects in a default schema, if no explicit schema is given.
`int`	`getDefaultSize(SqlType sqlType)` Gets the default size if no size given in model.
`String`	`getDriverClassName()` Gets the JDBC driver class name.
`String`	`getEmptyString()` Gets the empty string.
`int`	`getMaxScale(SqlType sqlType, int size)` Returns the maximum scale for a given SQL-type and size.
`int`	`getMaxSize(SqlType sqlType)` Returns the maximum size for a given SQL-type.
`DatabaseMetaData[]`	`getMetaData(BackendInfo backendInfo)` Gets the metadata from the backend.
`MigrationStrategy[]`	`getMigrationStrategy(ColumnMetaData column, String columnName, String comment, SqlType sqlType, int size, int scale, boolean nullable, Object defaultValue)` Determines the best migration strategy.
`ModelMetaData`	`getModelMetaData(DatabaseMetaData[] metaData, String[] schemas, String... tableNames)` Retrieves the metadata.
`String`	`getName()` Gets the name of the backend.
`Set<String>`	`getReservedWords()` Gets the list of reserved words for this backend.
`TableMetaData`	`getTableMetaData(ModelMetaData modelMetaData, String tableName)` Gets the table meta data for a given table name.
`boolean`	`isCommunicationLinkException(SQLException ex)` Determines whether exception is a communication error.
`boolean`	`isConstraintException(SQLException ex)` Determines whether exception is a constraint violation.
`boolean`	`isDefaultEqual(ColumnMetaData column, SqlType sqlType, Object defaultValue)` Checks whether the column's default corresponds to the model's default value.
`boolean`	`isMatchingName(String name)` Checks whether the backend belongs to the given name.
`boolean`	`isMatchingUrl(String url)` Checks whether the backend belongs to the given jdbc url.
`boolean`	`isReleaseSavepointSupported()` Returns whether the backend supports releasing savepoints explicitly.
`boolean`	`isTemporaryName(String name)` Checks whether this is a temporary name. Returns whether an entity-, attribute- or index-name is temporary and should not be taken into account for migration or even used in the model. Depending on the backend, temporary names start with an underscore or some other lead string.
`SqlType[]`	`jdbcTypeToSqlType(int jdbcType, int size, int scale)` Converts the JDBC data type integer to a tentackle backend SqlTypes.
`boolean`	`needAliasForSubselect()` Returns whether backend needs an alias for a subselect.
`boolean`	`needSetLongWorkaround()` Checks whether we need a workaround for the (Ingres) setLong-Bug.
`boolean`	`needTxForFetchsize()` Checks for the (postgres) bug that fetchsize is ignored if not within a new transaction.
`String`	`optimizeSql(String sql)` Optimize SQL code. Replace WHERE 1=1 AND/OR to WHERE.
`int`	`setLeadingSelectParameters(BackendPreparedStatement stmt, int limit, int offset)` Sets optional parameters before applying the original parameters.
`int`	`setTrailingSelectParameters(BackendPreparedStatement stmt, int index, int limit, int offset)` Sets optional parameters after applying the original parameters.
`String`	`sqlAddColumn(String tableName, String columnName, String comment, SqlType sqlType, int size, int scale, boolean nullable, Object defaultValue)` Generates sql code to add a column.
`String`	`sqlAlterColumnComment(String tableName, String columnName, String comment)` Generates SQL code to alter the comment for an attribute.
`String`	`sqlAlterColumnDefault(String tableName, String columnName, SqlType sqlType, Object defaultValue)` Generates sql code to change the default value a column.
`String`	`sqlAlterColumnNullConstraint(String tableName, String columnName, boolean nullable)` Generates sql code to change the null-constraint of a column.
`String`	`sqlAlterColumnType(String tableName, String columnName, String comment, SqlType sqlType, int size, int scale, boolean nullable, Object defaultValue)` Generates sql code to change the datatype of a column.
`String`	`sqlAlterTableComment(String tableName, String comment)` Generates SQL code to alter the comment for a table.
`String`	`sqlAsBeforeTableAlias()` Gets the string before the table alias. In most databases the " AS " is optional and some don't accept it all.
`String`	`sqlComment(String text)` Create comment sql code that is interpreted as a comment by the backend.
`String`	`sqlCreateColumn(String columnName, String comment, SqlType sqlType, int size, int scale, boolean nullable, Object defaultValue, boolean primaryKey, boolean withTrailingComma)` Generates the attribute definition of a CREATE TABLE statement.
`String`	`sqlCreateColumnComment(String tableName, String columnName, String comment)` Generates SQL code to create the comment for an attribute.
`String`	`sqlCreateForeignKey(String referencingTableName, String referencingColumnName, String referencedTableName, String referencedColumnName, String foreignKeyName, boolean composite)` Generates the ALTER TABLE statement to add a foreign key constraint.
`String`	`sqlCreateIndex(String tableName, String indexName, boolean unique, String filterCondition, String... columnNames)` Generates the CREATE INDEX statement.
`String`	`sqlCreateTableClosing(String tableName, String comment)` Generates the last line of a CREATE TABLE statement.
`String`	`sqlCreateTableComment(String tableName, String comment)` Generates SQL code to create the comment for a table.
`String`	`sqlCreateTableIntro(String tableName, String comment)` Generates the first line of a CREATE TABLE statement.
`String`	`sqlDropColumn(String tableName, String columnName)` Generates sql code to drop a column.
`String`	`sqlDropForeignKey(String referencingTableName, String foreignKeyName)` Generates the sql statement to drop a foreign key constraint.
`String`	`sqlDropIndex(String schemaName, String tableNameWithoutSchema, String indexName)` Generates the DROP INDEX statement.
`String`	`sqlFunction(String functionName, String expression)` Creates an sql function expression.
`String`	`sqlJoin(JoinType type, String joinedTableName, String joinedTableAlias, String join)` Creates a join clause.
`void`	`sqlJoinSelects(JoinType type, boolean addColumns, StringBuilder select, String joinSelect, String joinSelectIdAlias, String joinAlias, String join)` Generate SQL code for joining a table to an existing select.
`String`	`sqlJoinSelects(JoinType type, boolean addColumns, String select, String joinSelect, String joinSelectIdAlias, String joinAlias, String join)` Generate SQL code for joining a table to an existing select.
`String`	`sqlNextFromSequene(String name)` Creates the SQL string to retrieve the next id from a sequence.
`String`	`sqlRenameAndAlterColumnType(String tableName, String oldColumnName, String newColumnName, String comment, SqlType sqlType, int size, int scale, boolean nullable, Object defaultValue)` Generates sql code to rename a column.
`String`	`sqlRenameColumn(String tableName, String oldColumnName, String newColumnName)` Generates sql code to rename a column.
`boolean`	`sqlRequiresExtraCommit()` According to the JDBC-specs `Connection.setAutoCommit(boolean)`(true) should commit, but some backends require an extra `Connection.commit()`.
`boolean`	`sqlResultSetIsClosedSupported()` Determines whether the jdbc driver supports `ResultSet.isClosed()`.
`String`	`sqlTypeToString(SqlType sqlType, int size)` Converts the java SQL-type to the database type name.
`String`	`sqlUpdateToNotNull(String tableName, String columnName, SqlType sqlType, Object defaultValue)` Generates code to update a column to a non-null value.
`boolean`	`supportsSequences()` True if backend provides transactionless sequences.
`String`	`toQuotedString(String str)` Converts a string to a string enclosed in single quotes.
`String`	`valueToLiteral(SqlType sqlType, Object value)` Conberts a type and value to a literal string.

- Field Detail
  - SQL_WHERE
```
static final String SQL_WHERE
```
    WHERE string.
    
    See Also:
    
    Constant Field Values
  - SQL_SELECT
```
static final String SQL_SELECT
```
    SELECT string.
    
    See Also:
    
    Constant Field Values
  - SQL_SELECT_ALL_FROM
```
static final String SQL_SELECT_ALL_FROM
```
    SELECT * FROM string.
    
    See Also:
    
    Constant Field Values
  - SQL_DELETE
```
static final String SQL_DELETE
```
    DELETE string.
    
    See Also:
    
    Constant Field Values
  - SQL_UPDATE
```
static final String SQL_UPDATE
```
    UPDATE string.
    
    See Also:
    
    Constant Field Values
  - SQL_INSERT_INTO
```
static final String SQL_INSERT_INTO
```
    INSERT INTO string.
    
    See Also:
    
    Constant Field Values
  - SQL_LEFT_PARENTHESIS
```
static final String SQL_LEFT_PARENTHESIS
```
    opening bracket.
    
    See Also:
    
    Constant Field Values
  - SQL_RIGHT_PARENTHESIS
```
static final String SQL_RIGHT_PARENTHESIS
```
    closing bracket.
    
    See Also:
    
    Constant Field Values
  - SQL_INSERT_VALUES
```
static final String SQL_INSERT_VALUES
```
    (VALUES) string for insert.
    
    See Also:
    
    Constant Field Values
  - SQL_SET
```
static final String SQL_SET
```
    SET string.
    
    See Also:
    
    Constant Field Values
  - SQL_FROM
```
static final String SQL_FROM
```
    FROM string.
    
    See Also:
    
    Constant Field Values
  - SQL_AND
```
static final String SQL_AND
```
    AND string.
    
    See Also:
    
    Constant Field Values
  - SQL_OR
```
static final String SQL_OR
```
    OR string.
    
    See Also:
    
    Constant Field Values
  - SQL_NOT
```
static final String SQL_NOT
```
    NOT string.
    
    See Also:
    
    Constant Field Values
  - SQL_ANDNOT
```
static final String SQL_ANDNOT
```
    AND NOT string.
    
    See Also:
    
    Constant Field Values
  - SQL_ORNOT
```
static final String SQL_ORNOT
```
    OR NOT string.
    
    See Also:
    
    Constant Field Values
  - SQL_COMMA
```
static final String SQL_COMMA
```
    comma separator.
    
    See Also:
    
    Constant Field Values
  - SQL_PAR
```
static final String SQL_PAR
```
    ? string.
    
    See Also:
    
    Constant Field Values
  - SQL_EQUAL
```
static final String SQL_EQUAL
```
    = operator string.
    
    See Also:
    
    Constant Field Values
  - SQL_NOTEQUAL
```
static final String SQL_NOTEQUAL
```
    <> operator string.
    
    See Also:
    
    Constant Field Values
  - SQL_LESS
```
static final String SQL_LESS
```
    < operator string.
    
    See Also:
    
    Constant Field Values
  - SQL_GREATER
```
static final String SQL_GREATER
```
    > operator string.
    
    See Also:
    
    Constant Field Values
  - SQL_LESSOREQUAL
```
static final String SQL_LESSOREQUAL
```
    <= operator string.
    
    See Also:
    
    Constant Field Values
  - SQL_GREATEROREQUAL
```
static final String SQL_GREATEROREQUAL
```
    >= operator string.
    
    See Also:
    
    Constant Field Values
  - SQL_LIKE
```
static final String SQL_LIKE
```
    LIKE operator string.
    
    See Also:
    
    Constant Field Values
  - SQL_NOTLIKE
```
static final String SQL_NOTLIKE
```
    NOT LIKE operator string.
    
    See Also:
    
    Constant Field Values
  - SQL_EQUAL_ZERO
```
static final String SQL_EQUAL_ZERO
```
    =0 string.
    
    See Also:
    
    Constant Field Values
  - SQL_NOTEQUAL_ZERO
```
static final String SQL_NOTEQUAL_ZERO
```
    <>0 string.
    
    See Also:
    
    Constant Field Values
  - SQL_COMMA_PAR
```
static final String SQL_COMMA_PAR
```
    Parameter ,? string.
    
    See Also:
    
    Constant Field Values
  - SQL_PAR_COMMA
```
static final String SQL_PAR_COMMA
```
    Parameter ?, string.
    
    See Also:
    
    Constant Field Values
  - SQL_EQUAL_PAR
```
static final String SQL_EQUAL_PAR
```
    Parameter =? string.
    
    See Also:
    
    Constant Field Values
  - SQL_EQUAL_PAR_COMMA
```
static final String SQL_EQUAL_PAR_COMMA
```
    Parameter =?, string.
    
    See Also:
    
    Constant Field Values
  - SQL_NOTEQUAL_PAR
```
static final String SQL_NOTEQUAL_PAR
```
    Parameter <>? string.
    
    See Also:
    
    Constant Field Values
  - SQL_GREATER_PAR
```
static final String SQL_GREATER_PAR
```
    Parameter >? string.
    
    See Also:
    
    Constant Field Values
  - SQL_GREATEROREQUAL_PAR
```
static final String SQL_GREATEROREQUAL_PAR
```
    Parameter ≥? string.
    
    See Also:
    
    Constant Field Values
  - SQL_LESS_PAR
```
static final String SQL_LESS_PAR
```
    Parameter <? string.
    
    See Also:
    
    Constant Field Values
  - SQL_LESSOREQUAL_PAR
```
static final String SQL_LESSOREQUAL_PAR
```
    Parameter <=? string.
    
    See Also:
    
    Constant Field Values
  - SQL_LIKE_PAR
```
static final String SQL_LIKE_PAR
```
    Parameter LIKE ? string.
    
    See Also:
    
    Constant Field Values
  - SQL_NOTLIKE_PAR
```
static final String SQL_NOTLIKE_PAR
```
    Parameter NOT LIKE ? string.
    
    See Also:
    
    Constant Field Values
  - SQL_ALLSTAR
```
static final String SQL_ALLSTAR
```
    '*' all string.
    
    See Also:
    
    Constant Field Values
  - SQL_PLUS_ONE
```
static final String SQL_PLUS_ONE
```
    +1 string.
    
    See Also:
    
    Constant Field Values
  - SQL_WHEREALL
```
static final String SQL_WHEREALL
```
    "WHERE 1=1" allows AND to be added.
    
    See Also:
    
    Constant Field Values
  - SQL_WHERENOTHING
```
static final String SQL_WHERENOTHING
```
    "WHERE 1=0" to select nothing.
    
    See Also:
    
    Constant Field Values
  - SQL_WHEREAND
```
static final String SQL_WHEREAND
```
    SQL_WHEREALL + AND will be replaced by... SQL_WHERE.
    
    See Also:
    
    Constant Field Values
  - SQL_WHEREOR
```
static final String SQL_WHEREOR
```
    SQL_WHEREALL + OR will be replaced by... SQL_WHERE.
    
    See Also:
    
    Constant Field Values
  - SQL_ISNULL
```
static final String SQL_ISNULL
```
    IS NULL string.
    
    See Also:
    
    Constant Field Values
  - SQL_ISNOTNULL
```
static final String SQL_ISNOTNULL
```
    IS NOT NULL string.
    
    See Also:
    
    Constant Field Values
  - SQL_ORDERBY
```
static final String SQL_ORDERBY
```
    ORDER BY string.
    
    See Also:
    
    Constant Field Values
  - SQL_SORTASC
```
static final String SQL_SORTASC
```
    sort ASC string.
    
    See Also:
    
    Constant Field Values
  - SQL_SORTDESC
```
static final String SQL_SORTDESC
```
    sort DESC string.
    
    See Also:
    
    Constant Field Values
  - SQL_GROUPBY
```
static final String SQL_GROUPBY
```
    GROUP BY string.
    
    See Also:
    
    Constant Field Values
  - SQL_MAX
```
static final String SQL_MAX
```
    MAX function name.
    
    See Also:
    
    Constant Field Values
  - SQL_MIN
```
static final String SQL_MIN
```
    MAX function name.
    
    See Also:
    
    Constant Field Values
  - SQL_EXISTS
```
static final String SQL_EXISTS
```
    SQL EXISTS clause with SELECT 1 and opening left parenthesis.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - isMatchingUrl
```
boolean isMatchingUrl(String url)
```
    Checks whether the backend belongs to the given jdbc url.
    
    Parameters:
    
    url - the jdbc url
    
    Returns:
    
    true if matches
  - isMatchingName
```
boolean isMatchingName(String name)
```
    Checks whether the backend belongs to the given name.
    
    Parameters:
    
    name - the backend's name
    
    Returns:
    
    true if matches
  - getName
```
String getName()
```
    Gets the name of the backend.
    
    Returns:
    
    the name
  - getDriverClassName
```
String getDriverClassName()
```
    Gets the JDBC driver class name.
    
    Returns:
    
    the class name
  - createConnection
```
Connection createConnection(String url,
                            String username,
                            char[] password)
                     throws SQLException
```
    Creates a jdbc connection.
    
    Parameters:
    
    url - the jdbc url
    
    username - the username
    
    password - the password
    
    Returns:
    
    the created connection
    
    Throws:
    
    SQLException - if connection could not be established
  - getMetaData
```
DatabaseMetaData[] getMetaData(BackendInfo backendInfo)
                        throws SQLException
```
    Gets the metadata from the backend.
    Important: the connection of the metadata is open!
    
    Parameters:
    
    backendInfo - the backend info
    
    Returns:
    
    the metadata, may be more than one if schemas set in backendInfo
    
    Throws:
    
    SQLException - if failed
  - isTemporaryName
```
boolean isTemporaryName(String name)
```
    Checks whether this is a temporary name.
    Returns whether an entity-, attribute- or index-name is temporary and should not be taken into account for migration or even used in the model.
    Depending on the backend, temporary names start with an underscore or some other lead string.
    
    Parameters:
    
    name - the name
    
    Returns:
    
    true temporary (invalid) name
  - buildSelectSql
```
void buildSelectSql(StringBuilder sqlBuilder,
                    boolean writeLock,
                    int limit,
                    int offset)
```
    Creates a select statement string from an inner sql string.
    sqlBuilder is anything as FROM... WHERE... ORDER BY....
    It is decorated with a leading SELECT plus optional clauses like for the given parameters.
    
    Parameters:
    
    sqlBuilder - the sql builder, initially containing the inner sql without leading SELECT.
    
    writeLock - true select should write lock
    
    limit - the limit value, ≤ 0 if no limit clause
    
    offset - the offset value, ≤ 0 if no offset clause
  - buildSelectSql
```
String buildSelectSql(String sql,
                      boolean writeLock,
                      int limit,
                      int offset)
```
    Creates a select statement string from an inner sql string.
    sqlBuilder is anything as FROM... WHERE... ORDER BY....
    It is decorated with a leading SELECT plus optional clauses like for the given parameters.
    
    Parameters:
    
    sql - the sql without leading SELECT.
    
    writeLock - true select should write lock
    
    limit - the limit value, ≤ 0 if no limit clause
    
    offset - the offset value, ≤ 0 if no offset clause
    
    Returns:
    
    the select statement
  - setLeadingSelectParameters
```
int setLeadingSelectParameters(BackendPreparedStatement stmt,
                               int limit,
                               int offset)
```
    Sets optional parameters before applying the original parameters.
    
    Parameters:
    
    stmt - the prepared statement
    
    limit - the limit value, ≤ 0 if no limit clause
    
    offset - the offset value, ≤ 0 if no offset clause
    
    Returns:
    
    the next parameter index
  - setTrailingSelectParameters
```
int setTrailingSelectParameters(BackendPreparedStatement stmt,
                                int index,
                                int limit,
                                int offset)
```
    Sets optional parameters after applying the original parameters.
    
    Parameters:
    
    stmt - the prepared statement
    
    index - the first parameter index
    
    limit - the limit value, ≤ 0 if no limit clause
    
    offset - the offset value, ≤ 0 if no offset clause
    
    Returns:
    
    the next parameter index
  - getEmptyString
```
String getEmptyString()
```
    Gets the empty string.
    Some dbms (most famous: Oracle) handle empty strings as null. In such cases the empty string (e.g. Oracle) may consist of a single blank or whatever.
    
    Returns:
    
    the empty string (never null)
  - sqlRequiresExtraCommit
```
boolean sqlRequiresExtraCommit()
```
    According to the JDBC-specs Connection.setAutoCommit(boolean)(true) should commit, but some backends require an extra Connection.commit().
    
    Returns:
    
    true if the database needs an extra commit
  - sqlResultSetIsClosedSupported
```
boolean sqlResultSetIsClosedSupported()
```
    Determines whether the jdbc driver supports ResultSet.isClosed().
    
    Returns:
    
    true if the driver supports it
  - getCoalesceKeyword
```
String getCoalesceKeyword()
```
    Gets the keyword for the COALESCE function.
    
    Returns:
    
    the keyword
  - allowsExpressionsReferringToTablesBeingUpdated
```
boolean allowsExpressionsReferringToTablesBeingUpdated()
```
    Determines whether backend allows expressions referring to tables being updated.
    
    Returns:
    
    true if allowed
  - supportsSequences
```
boolean supportsSequences()
```
    True if backend provides transactionless sequences.
    
    Returns:
    
    true if database supports sequences
  - sqlAsBeforeTableAlias
```
String sqlAsBeforeTableAlias()
```
    Gets the string before the table alias.
    In most databases the " AS " is optional and some don't accept it all.
    
    Returns:
    
    the as-string
  - needAliasForSubselect
```
boolean needAliasForSubselect()
```
    Returns whether backend needs an alias for a subselect.
    
    Returns:
    
    true if subselect needs an alias.
  - sqlNextFromSequene
```
String sqlNextFromSequene(String name)
```
    Creates the SQL string to retrieve the next id from a sequence.
    
    Parameters:
    
    name - the name of the sequence
    
    Returns:
    
    the SQL code
  - sqlComment
```
String sqlComment(String text)
```
    Create comment sql code that is interpreted as a comment by the backend.
    
    Parameters:
    
    text - any text, single or multiline
    
    Returns:
    
    the comment, null if text was null
  - sqlJoin
```
String sqlJoin(JoinType type,
               String joinedTableName,
               String joinedTableAlias,
               String join)
```
    Creates a join clause.
    
    Parameters:
    
    type - the join type
    
    joinedTableName - the joined tablename
    
    joinedTableAlias - the joined table alias, null if none
    
    join - the join expression
    
    Returns:
    
    the sql code
  - sqlFunction
```
String sqlFunction(String functionName,
                   String expression)
```
    Creates an sql function expression.
    Example:
```
  sqlFunction("max", CN_ID) --> "MAX(id)"
 
```
    Parameters:
    
    functionName - the function name, will be translated to uppercase
    
    expression - the expression, may be null
    
    Returns:
    
    the sql code
  - needSetLongWorkaround
```
boolean needSetLongWorkaround()
```
    Checks whether we need a workaround for the (Ingres) setLong-Bug.
    
    Returns:
    
    true if workaround needed
  - needTxForFetchsize
```
boolean needTxForFetchsize()
```
    Checks for the (postgres) bug that fetchsize is ignored if not within a new transaction.
    
    Returns:
    
    true if start tx
  - isConstraintException
```
boolean isConstraintException(SQLException ex)
```
    Determines whether exception is a constraint violation.
    
    Parameters:
    
    ex - the exception
    
    Returns:
    
    true if constraint violation
  - isCommunicationLinkException
```
boolean isCommunicationLinkException(SQLException ex)
```
    Determines whether exception is a communication error.
    
    Parameters:
    
    ex - the exception
    
    Returns:
    
    true if comlink down or alike
  - getMaxSize
```
int getMaxSize(SqlType sqlType)
```
    Returns the maximum size for a given SQL-type.
    
    Parameters:
    
    sqlType - the SQL-type
    
    Returns:
    
    the maximum size, 0 if unlimited, -1 if type without size
  - getMaxScale
```
int getMaxScale(SqlType sqlType,
                int size)
```
    Returns the maximum scale for a given SQL-type and size.
    
    Parameters:
    
    sqlType - the SQL-type
    
    size - the size, 0 if unlimited
    
    Returns:
    
    the maximum scale, 0 if unlimited
  - getDefaultSize
```
int getDefaultSize(SqlType sqlType)
```
    Gets the default size if no size given in model.
    
    Parameters:
    
    sqlType - the SQL-type
    
    Returns:
    
    the default size, 0 if no default size
  - getDefaultSchema
```
String getDefaultSchema()
```
    Gets the default schema name.
    Some backends store the objects in a default schema, if no explicit schema is given.
    
    Returns:
    
    the defailt schema, null if none
  - getReservedWords
```
Set<String> getReservedWords()
```
    Gets the list of reserved words for this backend.
    
    Returns:
    
    the list of reserved words
  - assertValidName
```
void assertValidName(String nameType,
                     String name)
```
    Asserts that given string is a valid name and usage.
    
    Parameters:
    
    nameType - the type/usage of the name
    
    name - the name
    
    Throws:
    
    BackendException - if invalid name
  - getBackendId
```
String getBackendId(Connection connection)
```
    Determines the unique id or name used by the backend for a given connection.
    Useful to figure out the corresponding ManagedConnection from the backend's logfiles.
    
    Parameters:
    
    connection - the jdbc connection
    
    Returns:
    
    the backend id, null if none
  - getModelMetaData
```
ModelMetaData getModelMetaData(DatabaseMetaData[] metaData,
                               String[] schemas,
                               String... tableNames)
```
    Retrieves the metadata.
    
    Parameters:
    
    metaData - the meta data for the whole database
    
    schemas - the optional schemas to filter tables, null if no filter
    
    tableNames - the tables of the model
    
    Returns:
    
    the meta data, null if no such table
  - createColumnMetaData
```
ColumnMetaData createColumnMetaData(TableMetaData tableMetaData)
```
    Creates a column meta data instance.
    
    Parameters:
    
    tableMetaData - the table meta data this column belongs to
    
    Returns:
    
    the meta data
  - createTableMetaData
```
TableMetaData createTableMetaData(ModelMetaData metaData,
                                  String tableName)
```
    Creates a meta data instance.
    
    Parameters:
    
    metaData - the whole meta data
    
    tableName - the model's table name
    
    Returns:
    
    the meta data
  - createIndexMetaData
```
IndexMetaData createIndexMetaData(TableMetaData tableMetaData)
```
    Creates an index meta data instance.
    
    Parameters:
    
    tableMetaData - the table meta data this index belongs to
    
    Returns:
    
    the meta data
  - createIndexColumnMetaData
```
IndexColumnMetaData createIndexColumnMetaData(IndexMetaData indexMetaData)
```
    Creates an index column meta data instance.
    
    Parameters:
    
    indexMetaData - the meta meta data this column belongs to
    
    Returns:
    
    the meta data
  - sqlTypeToString
```
String sqlTypeToString(SqlType sqlType,
                       int size)
```
    Converts the java SQL-type to the database type name.
    
    Parameters:
    
    sqlType - the java sql type
    
    size - the column's size
    
    Returns:
    
    the corresponding type string
  - columnTypeToString
```
String columnTypeToString(SqlType sqlType,
                          int size,
                          int scale)
```
    Converts an sqltype, size and scale to a database type declaration.
    
    Parameters:
    
    sqlType - the SQL type
    
    size - the size
    
    scale - the scale
    
    Returns:
    
    the type definition
  - columnTypeNullDefaultToString
```
String columnTypeNullDefaultToString(String columnName,
                                     SqlType sqlType,
                                     int size,
                                     int scale,
                                     boolean nullable,
                                     Object defaultValue)
```
    Converts an sqltype, size, scale, nullable and default value to a database type declaration.
    
    Parameters:
    
    columnName - the database column name
    
    sqlType - the JDBC sql type
    
    size - the optional size
    
    scale - the optional scale
    
    nullable - true if NULL, else NOT NULL
    
    defaultValue - the optional default value
    
    Returns:
    
    the SQL code
  - valueToLiteral
```
String valueToLiteral(SqlType sqlType,
                      Object value)
```
    Conberts a type and value to a literal string.
    
    Parameters:
    
    sqlType - the sql type
    
    value - the value
    
    Returns:
    
    the constant
  - sqlCreateTableIntro
```
String sqlCreateTableIntro(String tableName,
                           String comment)
```
    Generates the first line of a CREATE TABLE statement.
    
    Parameters:
    
    tableName - the tablename with optional schema separated by a dot
    
    comment - optional comment, null if none
    
    Returns:
    
    the SQL code including the opening bracket
  - sqlCreateTableClosing
```
String sqlCreateTableClosing(String tableName,
                             String comment)
```
    Generates the last line of a CREATE TABLE statement.
    
    Parameters:
    
    tableName - the tablename with optional schema separated by a dot
    
    comment - optional comment, null if none
    
    Returns:
    
    the SQL code including the closing bracket
  - sqlCreateTableComment
```
String sqlCreateTableComment(String tableName,
                             String comment)
```
    Generates SQL code to create the comment for a table.
    
    Parameters:
    
    tableName - the table name
    
    comment - optional comment, null if none
    
    Returns:
    
    the SQL code, empty string if comment is created via sqlCreateTableIntro(java.lang.String, java.lang.String) or sqlCreateTableClosing(java.lang.String, java.lang.String)
  - sqlAlterTableComment
```
String sqlAlterTableComment(String tableName,
                            String comment)
```
    Generates SQL code to alter the comment for a table.
    
    Parameters:
    
    tableName - the table name
    
    comment - optional comment, null to clear
    
    Returns:
    
    the SQL code
  - sqlCreateColumn
```
String sqlCreateColumn(String columnName,
                       String comment,
                       SqlType sqlType,
                       int size,
                       int scale,
                       boolean nullable,
                       Object defaultValue,
                       boolean primaryKey,
                       boolean withTrailingComma)
```
    Generates the attribute definition of a CREATE TABLE statement.
    
    Parameters:
    
    columnName - the database column name
    
    comment - optional comment, null if none
    
    sqlType - the JDBC sql type
    
    size - the optional size
    
    scale - the optional scale
    
    nullable - true if NULL, else NOT NULL
    
    defaultValue - the optional default value
    
    primaryKey - true if this is a primary key
    
    withTrailingComma - true if append a comma
    
    Returns:
    
    the SQL code
  - isDefaultEqual
```
boolean isDefaultEqual(ColumnMetaData column,
                       SqlType sqlType,
                       Object defaultValue)
```
    Checks whether the column's default corresponds to the model's default value.
    
    Parameters:
    
    column - the column to inspect
    
    sqlType - the sql type
    
    defaultValue - the model's default value
    
    Returns:
    
    true if same
  - getMigrationStrategy
```
MigrationStrategy[] getMigrationStrategy(ColumnMetaData column,
                                         String columnName,
                                         String comment,
                                         SqlType sqlType,
                                         int size,
                                         int scale,
                                         boolean nullable,
                                         Object defaultValue)
```
    Determines the best migration strategy.
    
    Parameters:
    
    column - old column meta data
    
    columnName - new column name
    
    comment - new comment
    
    sqlType - new sql type
    
    size - new size
    
    scale - new scale
    
    nullable - new nullable
    
    defaultValue - new default
    
    Returns:
    
    the strategies in order to achieve the migration
  - sqlRenameColumn
```
String sqlRenameColumn(String tableName,
                       String oldColumnName,
                       String newColumnName)
```
    Generates sql code to rename a column.
    
    Parameters:
    
    tableName - the tablename
    
    oldColumnName - the old column name
    
    newColumnName - the new column name
    
    Returns:
    
    the SQL code, null if need full spec sqlRenameAndAlterColumnType below
  - sqlRenameAndAlterColumnType
```
String sqlRenameAndAlterColumnType(String tableName,
                                   String oldColumnName,
                                   String newColumnName,
                                   String comment,
                                   SqlType sqlType,
                                   int size,
                                   int scale,
                                   boolean nullable,
                                   Object defaultValue)
```
    Generates sql code to rename a column.
    
    Parameters:
    
    tableName - the tablename
    
    oldColumnName - the old column name
    
    newColumnName - the new column name
    
    comment - optional comment, null if none
    
    sqlType - the JDBC sql type
    
    size - the optional size
    
    scale - the optional scale
    
    nullable - true if NULL, else NOT NULL
    
    defaultValue - the optional default value
    
    Returns:
    
    the SQL code
  - sqlAddColumn
```
String sqlAddColumn(String tableName,
                    String columnName,
                    String comment,
                    SqlType sqlType,
                    int size,
                    int scale,
                    boolean nullable,
                    Object defaultValue)
```
    Generates sql code to add a column.
    
    Parameters:
    
    tableName - the tablename
    
    columnName - the new column name
    
    comment - optional comment, null if none
    
    sqlType - the JDBC sql type
    
    size - the optional size
    
    scale - the optional scale
    
    nullable - true if NULL, else NOT NULL
    
    defaultValue - the optional default value
    
    Returns:
    
    the SQL code
  - sqlDropColumn
```
String sqlDropColumn(String tableName,
                     String columnName)
```
    Generates sql code to drop a column.
    
    Parameters:
    
    tableName - the tablename
    
    columnName - the new column name
    
    Returns:
    
    the SQL code
  - sqlAlterColumnType
```
String sqlAlterColumnType(String tableName,
                          String columnName,
                          String comment,
                          SqlType sqlType,
                          int size,
                          int scale,
                          boolean nullable,
                          Object defaultValue)
```
    Generates sql code to change the datatype of a column.
    
    Parameters:
    
    tableName - the tablename
    
    columnName - the new column name
    
    comment - optional comment, null if none
    
    sqlType - the JDBC sql type
    
    size - the optional size
    
    scale - the optional scale
    
    nullable - true if NULL, else NOT NULL
    
    defaultValue - the optional default value
    
    Returns:
    
    the SQL code
  - sqlUpdateToNotNull
```
String sqlUpdateToNotNull(String tableName,
                          String columnName,
                          SqlType sqlType,
                          Object defaultValue)
```
    Generates code to update a column to a non-null value.
    
    Parameters:
    
    tableName - the tablename
    
    columnName - the column name
    
    sqlType - the sql type
    
    defaultValue - the optional default value if defined in the model
    
    Returns:
    
    the SQL code
  - sqlAlterColumnNullConstraint
```
String sqlAlterColumnNullConstraint(String tableName,
                                    String columnName,
                                    boolean nullable)
```
    Generates sql code to change the null-constraint of a column.
    
    Parameters:
    
    tableName - the tablename
    
    columnName - the new column name
    
    nullable - true if NULL, else NOT NULL
    
    Returns:
    
    the SQL code, null if need sqlAlterColumnType(java.lang.String, java.lang.String, java.lang.String, org.tentackle.sql.SqlType, int, int, boolean, java.lang.Object)
  - sqlAlterColumnDefault
```
String sqlAlterColumnDefault(String tableName,
                             String columnName,
                             SqlType sqlType,
                             Object defaultValue)
```
    Generates sql code to change the default value a column.
    
    Parameters:
    
    tableName - the tablename
    
    columnName - the new column name
    
    sqlType - the JDBC sql type
    
    defaultValue - the optional default value
    
    Returns:
    
    the SQL code, null if need sqlAlterColumnType(java.lang.String, java.lang.String, java.lang.String, org.tentackle.sql.SqlType, int, int, boolean, java.lang.Object)
  - sqlCreateColumnComment
```
String sqlCreateColumnComment(String tableName,
                              String columnName,
                              String comment)
```
    Generates SQL code to create the comment for an attribute.
    
    Parameters:
    
    tableName - the table name
    
    columnName - the column name
    
    comment - optional comment, null if none
    
    Returns:
    
    the SQL code, empty string if comment is created via sqlCreateColumn(java.lang.String, java.lang.String, org.tentackle.sql.SqlType, int, int, boolean, java.lang.Object, boolean, boolean)
  - sqlCreateIndex
```
String sqlCreateIndex(String tableName,
                      String indexName,
                      boolean unique,
                      String filterCondition,
                      String... columnNames)
```
    Generates the CREATE INDEX statement.
    
    Parameters:
    
    tableName - the table name
    
    indexName - the name of the index
    
    unique - true if index is unique
    
    filterCondition - the filter condition (null if none)
    
    columnNames - the column names (with a leading '-' if descending)
    
    Returns:
    
    the SQL code
  - sqlDropIndex
```
String sqlDropIndex(String schemaName,
                    String tableNameWithoutSchema,
                    String indexName)
```
    Generates the DROP INDEX statement.
    
    Parameters:
    
    schemaName - the optional schema, null if none
    
    tableNameWithoutSchema - the table name without the schema
    
    indexName - the name of the index
    
    Returns:
    
    the SQL code
  - sqlCreateForeignKey
```
String sqlCreateForeignKey(String referencingTableName,
                           String referencingColumnName,
                           String referencedTableName,
                           String referencedColumnName,
                           String foreignKeyName,
                           boolean composite)
```
    Generates the ALTER TABLE statement to add a foreign key constraint.
    
    Parameters:
    
    referencingTableName - the referencing foreign table name
    
    referencingColumnName - the referencing foreign column name
    
    referencedTableName - the referenced primary table name
    
    referencedColumnName - the referenced primary column name
    
    foreignKeyName - the name of the foreign key
    
    composite - true if referencing table is a component of the referenced table
    
    Returns:
    
    the SQL code
  - sqlDropForeignKey
```
String sqlDropForeignKey(String referencingTableName,
                         String foreignKeyName)
```
    Generates the sql statement to drop a foreign key constraint.
    
    Parameters:
    
    referencingTableName - the referencing foreign table name
    
    foreignKeyName - the name of the foreign key
    
    Returns:
    
    the SQL code
  - sqlAlterColumnComment
```
String sqlAlterColumnComment(String tableName,
                             String columnName,
                             String comment)
```
    Generates SQL code to alter the comment for an attribute.
    
    Parameters:
    
    tableName - the table name
    
    columnName - the column name
    
    comment - optional comment, null to clear
    
    Returns:
    
    the SQL code, null if use sqlRenameAndAlterColumnType(java.lang.String, java.lang.String, java.lang.String, java.lang.String, org.tentackle.sql.SqlType, int, int, boolean, java.lang.Object) instead
  - sqlJoinSelects
```
void sqlJoinSelects(JoinType type,
                    boolean addColumns,
                    StringBuilder select,
                    String joinSelect,
                    String joinSelectIdAlias,
                    String joinAlias,
                    String join)
```
    Generate SQL code for joining a table to an existing select.
    
    Parameters:
    
    type - the join type
    
    addColumns - true if columns of joined table should be added to the result set
    
    select - the original select statement
    
    joinSelect - the select to join with the original sql or just a tablename
    
    joinSelectIdAlias - extra id alias to add to the joined select, null if none
    
    joinAlias - the alias of the joined select
    
    join - the join clause
  - sqlJoinSelects
```
String sqlJoinSelects(JoinType type,
                      boolean addColumns,
                      String select,
                      String joinSelect,
                      String joinSelectIdAlias,
                      String joinAlias,
                      String join)
```
    Generate SQL code for joining a table to an existing select.
    
    Parameters:
    
    type - the join type
    
    addColumns - true if columns of joined table should be added to the result set
    
    select - the original select statement
    
    joinSelect - the select to join with the original sql or just a tablename
    
    joinSelectIdAlias - extra id alias to add to the joined select, null if none
    
    joinAlias - the alias of the joined select
    
    join - the join clause
    
    Returns:
    
    the select statement
  - jdbcTypeToSqlType
```
SqlType[] jdbcTypeToSqlType(int jdbcType,
                            int size,
                            int scale)
```
    Converts the JDBC data type integer to a tentackle backend SqlTypes.
    There may be more than one sqltype returned!
    
    Parameters:
    
    jdbcType - the jdbc data type
    
    size - the column size
    
    scale - the column's scale
    
    Returns:
    
    the SqlTypes, empty array if no mapping available or no exact match (not generated by TT)
    
    See Also:
    
    Types
  - getTableMetaData
```
TableMetaData getTableMetaData(ModelMetaData modelMetaData,
                               String tableName)
```
    Gets the table meta data for a given table name.
    
    Parameters:
    
    modelMetaData - the model the table belongs to
    
    tableName - the model's table name
    
    Returns:
    
    the table data
  - toQuotedString
```
String toQuotedString(String str)
```
    Converts a string to a string enclosed in single quotes.
    
    Parameters:
    
    str - the string
    
    Returns:
    
    the quoted string
  - optimizeSql
```
String optimizeSql(String sql)
```
    Optimize SQL code.
    Replace WHERE 1=1 AND/OR to WHERE. Any remaining WHERE 1=1 will be removed too. If you don't want your statements getting optimized, use lowercase for those keywords.
    
    Parameters:
    
    sql - the original sql code
    
    Returns:
    
    the optimized sql code
  - isReleaseSavepointSupported
```
boolean isReleaseSavepointSupported()
```
    Returns whether the backend supports releasing savepoints explicitly. If not, the savepoints are released when the transaction finishs.
    
    Returns:
    
    true if release is supported, else false

Interface Backend

Field Summary

Method Summary

Field Detail

SQL_WHERE

SQL_SELECT

SQL_SELECT_ALL_FROM

SQL_DELETE

SQL_UPDATE

SQL_INSERT_INTO

SQL_LEFT_PARENTHESIS

SQL_RIGHT_PARENTHESIS

SQL_INSERT_VALUES

SQL_SET

SQL_FROM

SQL_AND

SQL_OR

SQL_NOT

SQL_ANDNOT

SQL_ORNOT

SQL_COMMA

SQL_PAR

SQL_EQUAL

SQL_NOTEQUAL

SQL_LESS

SQL_GREATER

SQL_LESSOREQUAL

SQL_GREATEROREQUAL

SQL_LIKE

SQL_NOTLIKE

SQL_EQUAL_ZERO

SQL_NOTEQUAL_ZERO

SQL_COMMA_PAR

SQL_PAR_COMMA

SQL_EQUAL_PAR

SQL_EQUAL_PAR_COMMA

SQL_NOTEQUAL_PAR

SQL_GREATER_PAR

SQL_GREATEROREQUAL_PAR

SQL_LESS_PAR

SQL_LESSOREQUAL_PAR

SQL_LIKE_PAR

SQL_NOTLIKE_PAR

SQL_ALLSTAR

SQL_PLUS_ONE

SQL_WHEREALL

SQL_WHERENOTHING

SQL_WHEREAND

SQL_WHEREOR

SQL_ISNULL

SQL_ISNOTNULL

SQL_ORDERBY

SQL_SORTASC

SQL_SORTDESC

SQL_GROUPBY

SQL_MAX

SQL_MIN

SQL_EXISTS

Method Detail

isMatchingUrl

isMatchingName

getName

getDriverClassName

createConnection

getMetaData

isTemporaryName

buildSelectSql

buildSelectSql

setLeadingSelectParameters

setTrailingSelectParameters

getEmptyString

sqlRequiresExtraCommit

sqlResultSetIsClosedSupported

getCoalesceKeyword

allowsExpressionsReferringToTablesBeingUpdated

supportsSequences

sqlAsBeforeTableAlias

needAliasForSubselect

sqlNextFromSequene

sqlComment