Module org.tentackle.sql

Package org.tentackle.sql.backends

Class Postgres

java.lang.Object

org.tentackle.sql.backends.AbstractBackend

org.tentackle.sql.backends.AbstractSql92Backend

org.tentackle.sql.backends.Postgres

All Implemented Interfaces:

Backend

@Service(Backend.class)
public class Postgres
extends AbstractSql92Backend

Backend for Postgres.

Author:

harald

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DEFAULT_SCHEMA	postgres' default schema.
static final String[]	RESERVED_WORDS_PG	array of additional reserved words.
static final String	SQL_LIMIT	LIMIT string.
static final String	SQL_LIMIT_PAR	LIMIT ? string.
static final String	SQL_OFFSET	OFFSET string.
static final String	SQL_OFFSET_PAR	OFFSET ? string.

Fields inherited from class org.tentackle.sql.backends.AbstractSql92Backend

RESERVED_WORDS_SQL92, SQL_COALESCE, SQL_FOR_UPDATE

Fields inherited from class org.tentackle.sql.backends.AbstractBackend

TYPE_BIGINT, TYPE_BIT, TYPE_BLOB, TYPE_BOOL, TYPE_BOOLEAN, TYPE_BYTE, TYPE_BYTEA, TYPE_CHAR_1, TYPE_CLOB, TYPE_DATE, TYPE_DATETIME, TYPE_DATETIME_YEAR_TO_SECOND, TYPE_DECIMAL, TYPE_DECIMAL_19, TYPE_DOUBLE, TYPE_DOUBLE_PRECISION, TYPE_FLOAT, TYPE_FLOAT4, TYPE_FLOAT8, TYPE_INT, TYPE_INT2, TYPE_INT4, TYPE_INT8, TYPE_INTEGER, TYPE_NCHAR_1, TYPE_NUMBER, TYPE_NUMBER_1, TYPE_NUMBER_10, TYPE_NUMBER_19, TYPE_NUMBER_5, TYPE_NVARCHAR, TYPE_NVARCHAR_MAX, TYPE_REAL, TYPE_SMALLFLOAT, TYPE_SMALLINT, TYPE_TEXT, TYPE_TIME, TYPE_TIMESTAMP, TYPE_TINYINT, TYPE_UUID, TYPE_VARBINARY_MAX, TYPE_VARCHAR

Fields inherited from interface org.tentackle.sql.Backend

SQL_ALLSTAR, SQL_ALTER_COLUMN, SQL_ALTER_INDEX, SQL_ALTER_TABLE, SQL_AND, SQL_ANDNOT, SQL_ARRAY_ALL, SQL_ARRAY_ALL_PAR, SQL_ARRAY_ANY, SQL_ARRAY_ANY_PAR, SQL_ARRAY_IN, SQL_ARRAY_IN_PAR, SQL_ARRAY_NOT_IN, SQL_ARRAY_NOT_IN_PAR, SQL_ARRAY_PAR, SQL_COMMA, SQL_COMMA_PAR, SQL_DELETE, SQL_DOT_STAR, SQL_EQUAL, SQL_EQUAL_PAR, SQL_EQUAL_PAR_COMMA, SQL_EQUAL_ZERO, SQL_EXISTS, SQL_FROM, SQL_GREATER, SQL_GREATER_PAR, SQL_GREATEROREQUAL, SQL_GREATEROREQUAL_PAR, SQL_GROUPBY, SQL_IF_EXISTS, SQL_INSERT_INTO, SQL_INSERT_VALUES, SQL_ISNOTNULL, SQL_ISNULL, SQL_LEFT_PARENTHESIS, SQL_LESS, SQL_LESS_PAR, SQL_LESSOREQUAL, SQL_LESSOREQUAL_PAR, SQL_LIKE, SQL_LIKE_PAR, SQL_MAX, SQL_MIN, SQL_NOT, SQL_NOTEQUAL, SQL_NOTEQUAL_PAR, SQL_NOTEQUAL_ZERO, SQL_NOTLIKE, SQL_NOTLIKE_PAR, SQL_OR, SQL_ORDERBY, SQL_ORNOT, SQL_PAR, SQL_PAR_COMMA, SQL_PLUS_ONE, SQL_RIGHT_PARENTHESIS, SQL_SELECT, SQL_SELECT_ALL_FROM, SQL_SET, SQL_SORTASC, SQL_SORTDESC, SQL_UPDATE, SQL_WHERE, SQL_WHEREALL, SQL_WHEREAND, SQL_WHERENOTHING, SQL_WHEREOR

Constructor Summary

Constructors

Constructor	Description
Postgres()	Creates the postgres backend.

Method Summary

Modifier and Type	Method	Description
void	buildSelectSql(StringBuilder sqlBuilder, boolean writeLock, int limit, int offset)	Creates a select statement string from an inner sql string.
ColumnMetaData	createColumnMetaData(TableMetaData tableMetaData)	Creates a column meta data instance.
IndexColumnMetaData	createIndexColumnMetaData(IndexMetaData indexMetaData)	Creates an index column meta data instance.
IndexMetaData	createIndexMetaData(TableMetaData tableMetaData)	Creates an index meta data instance.
ScriptRunner	createScriptRunner(Connection connection)	Creates a script runner instance.
protected String	extractWhereClause(String sql, int whereOffset)	Extracts the where clause from a given sql.
String	getBackendId(Connection connection)	Determines the unique id or name used by the backend for a given connection.
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.
int	getMaxSize(SqlType sqlType)	Returns the maximum size for a given SQL-type.
MigrationStrategy[]	getMigrationStrategy(ColumnMetaData column, String columnName, String comment, SqlType sqlType, int size, int scale, boolean nullable, Object defaultValue)	Determines the best migration strategy.
String	getName()	Gets the name of the backend.
Set<String>	getReservedWords()	Gets the list of reserved words for this backend.
boolean	isAliasRequiredForSubSelect()	Returns whether backend requires an alias for a sub-select.
boolean	isArrayOperatorSupported(String operator)	Returns whether the backend supports given array operator.
boolean	isClobSupported()	Returns whether the backend support CLOB types. If not, it will be emulated as VARCHAR with the maximum possible size.
protected boolean	isDropIfExistsSupported()	Adds "IF EXISTS" to drop clauses, if supported by the backend. Makes migration a little more robust in case the same SQL scripts are applied to different databases than those used to generate the migration scripts for.
boolean	isFilteredIndexSupported()	Returns whether backend supports filtered indexes.
boolean	isFunctionBasedIndexSupported()	Returns whether function based indexes are supported.
boolean	isMatchingUrl(String url)	Checks whether the backend belongs to the given jdbc url. If multiple backend implementations are provided for the same database type, only one backend should match the URL.
boolean	isReleaseSavepointSupported()	Returns whether the backend supports releasing savepoints explicitly.
boolean	isReservedSchemaName(String name)	Checks whether this is a reserved schema name for this backend.
boolean	isSequenceSupported()	True if backend provides locking-free sequences. Sequences must not take part in transactions, i.e.
boolean	isTransientTransactionException(SQLException ex)	Determines whether exception is transient and retrying the transaction may succeed. Typical transient exceptions are thrown when a deadlock is detected or when serialized transaction isolation is used.
boolean	isTxRequiredForFetchsize()	Checks for the (postgres) bug that fetch-size is ignored if not within a new transaction.
boolean	isUUIDSupported()	Returns whether the backend supports the UUID natively via JDBC setObject/getObject.
SqlType[]	jdbcTypeToSqlType(int jdbcType, int size, int scale)	Converts the JDBC data type integer to a tentackle backend SqlTypes.
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	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	sqlCreateColumnComment(String tableName, String columnName, String comment)	Generates SQL code to create the comment for an attribute.
String	sqlCreateSequence(String name, Long start, Long increment)	Creates the SQL string to create a sequence.
String	sqlCreateSequenceComment(String name, String comment)	Creates the SQL string to comment a sequence.
String	sqlCreateTableComment(String tableName, String comment)	Generates SQL code to create the comment for a table.
String	sqlNextFromSequence(String name)	Creates the SQL string to retrieve the next id from a sequence.
String	sqlTypeToString(SqlType sqlType, int size)	Converts the java SQL-type to the database type name.
String	toInternalType(String sqlTypeName)	Converts a backend specific type name to an internal name used by driver specific methods.

Methods inherited from class org.tentackle.sql.backends.AbstractSql92Backend

getCoalesceKeyword, isLeadingSelectMissing, sqlCreateForeignKey, sqlDropForeignKey

Methods inherited from class org.tentackle.sql.backends.AbstractBackend

assertValidName, buildSelectSql, columnTypeNullDefaultToString, columnTypeToString, createConnection, createPassword, createTableMetaData, getBlockCommentBegin, getBlockCommentBegins, getBlockCommentEnd, getBlockCommentEnds, getEmptyString, getMaxScale, getMetaData, getModelMetaData, getSingleLineComment, getSingleLineComments, getStatementSeparator, getStatementSeparators, getTableHeaders, getTableMetaData, isCommunicationLinkException, isConstraintException, isDatabaseInMemory, isDefaultEqual, isDeprecated, isDropIfExistsEnabled, isExceptionErrorCodeMatching, isExceptionStateMatching, isExceptionStateStartingWith, isExpressionReferringToTableBeingUpdatedSupported, isExtraCommitRequired, isMatchingName, isPosixEscapeSyntaxSupported, isReservedTableName, isReservedWord, isSchemaSupported, isTemporaryName, normalizeDefault, optimizeSql, setArray, setDropIfExistsEnabled, sqlAddColumn, sqlAlterColumnComment, sqlAlterColumnDefault, sqlAlterTableComment, sqlAsBeforeTableAlias, sqlComment, sqlCreateColumn, sqlCreateIndex, sqlCreateSchema, sqlCreateTableAttributeWithoutComment, sqlCreateTableClosing, sqlCreateTableIntro, sqlCreateTableIntroWithoutComment, sqlDropColumn, sqlDropIndex, sqlDropTable, sqlFunction, sqlJoin, sqlJoinSelects, sqlJoinSelects, sqlRenameAndAlterColumnType, sqlRenameColumn, sqlRenameIndex, sqlRenameTable, sqlUpdateToNotNull, toQuotedString, toString, validateVersion, valueToLiteral

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_SCHEMA

public static final String DEFAULT_SCHEMA

postgres' default schema.

See Also:

• Constant Field Values

SQL_LIMIT

public static final String SQL_LIMIT

LIMIT string.

See Also:

• Constant Field Values

SQL_OFFSET

public static final String SQL_OFFSET

OFFSET string.

See Also:

• Constant Field Values

SQL_LIMIT_PAR

public static final String SQL_LIMIT_PAR

LIMIT ? string.

See Also:

• Constant Field Values

SQL_OFFSET_PAR

public static final String SQL_OFFSET_PAR

OFFSET ? string.

See Also:

• Constant Field Values

RESERVED_WORDS_PG

public static final String[] RESERVED_WORDS_PG

array of additional reserved words.

Constructor Details

Postgres

public Postgres()

Creates the postgres backend.

Method Details

getReservedWords

public Set<String> getReservedWords()

Description copied from interface: Backend

Gets the list of reserved words for this backend.

Specified by:

getReservedWords in interface Backend

Overrides:

getReservedWords in class AbstractSql92Backend

Returns:

the set of reserved words

isMatchingUrl

public boolean isMatchingUrl(String url)

Description copied from interface: Backend

Checks whether the backend belongs to the given jdbc url.
If multiple backend implementations are provided for the same database type, only one backend should match the URL. The others must be selected via name.

Parameters:

url - the jdbc url

Returns:

true if matches

getName

public String getName()

Description copied from interface: Backend

Gets the name of the backend.

Returns:

the name

getDriverClassName

public String getDriverClassName()

Description copied from interface: Backend

Gets the JDBC driver class name.

Returns:

the class name

getBackendId

public String getBackendId(Connection connection)

Description copied from interface: Backend

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

isReleaseSavepointSupported

public boolean isReleaseSavepointSupported()

Description copied from interface: Backend

Returns whether the backend supports releasing savepoints explicitly. If not, the savepoints are released when the transaction finishs.

Specified by:

isReleaseSavepointSupported in interface Backend

Overrides:

isReleaseSavepointSupported in class AbstractBackend

Returns:

true if release is supported, else false

isReservedSchemaName

public boolean isReservedSchemaName(String name)

Description copied from interface: Backend

Checks whether this is a reserved schema name for this backend.

Specified by:

isReservedSchemaName in interface Backend

Overrides:

isReservedSchemaName in class AbstractBackend

Parameters:

name - the schema name

Returns:

true if reserved by backend

isTransientTransactionException

public boolean isTransientTransactionException(SQLException ex)

Description copied from interface: Backend

Determines whether exception is transient and retrying the transaction may succeed.
Typical transient exceptions are thrown when a deadlock is detected or when serialized transaction isolation is used.

Other transient errors are not covered by this method (e.g. connection timeouts, etc...).

Specified by:

isTransientTransactionException in interface Backend

Overrides:

isTransientTransactionException in class AbstractBackend

Parameters:

ex - the exception

Returns:

true if retrying the transaction may succeed

isClobSupported

public boolean isClobSupported()

Description copied from interface: Backend

Returns whether the backend support CLOB types.
If not, it will be emulated as VARCHAR with the maximum possible size.

Specified by:

isClobSupported in interface Backend

Overrides:

isClobSupported in class AbstractBackend

Returns:

true if supported, false if treat as varchar

isUUIDSupported

public boolean isUUIDSupported()

Description copied from interface: Backend

Returns whether the backend supports the UUID natively via JDBC setObject/getObject.

Specified by:

isUUIDSupported in interface Backend

Overrides:

isUUIDSupported in class AbstractBackend

Returns:

true if supported, false if mapped to VARCHAR(36)

isFilteredIndexSupported

public boolean isFilteredIndexSupported()

Description copied from interface: Backend

Returns whether backend supports filtered indexes.

Specified by:

isFilteredIndexSupported in interface Backend

Overrides:

isFilteredIndexSupported in class AbstractBackend

Returns:

true if supported, false if model will raise an error if filtered index is used

isFunctionBasedIndexSupported

public boolean isFunctionBasedIndexSupported()

Description copied from interface: Backend

Returns whether function based indexes are supported.

Specified by:

isFunctionBasedIndexSupported in interface Backend

Overrides:

isFunctionBasedIndexSupported in class AbstractBackend

Returns:

true if supported

isTxRequiredForFetchsize

public boolean isTxRequiredForFetchsize()

Description copied from interface: Backend

Checks for the (postgres) bug that fetch-size is ignored if not within a new transaction.

Specified by:

isTxRequiredForFetchsize in interface Backend

Overrides:

isTxRequiredForFetchsize in class AbstractBackend

Returns:

true if start tx

isAliasRequiredForSubSelect

public boolean isAliasRequiredForSubSelect()

Description copied from interface: Backend

Returns whether backend requires an alias for a sub-select.

Specified by:

isAliasRequiredForSubSelect in interface Backend

Overrides:

isAliasRequiredForSubSelect in class AbstractBackend

Returns:

true if sub-select needs an alias.

buildSelectSql

public void buildSelectSql(StringBuilder sqlBuilder,
 boolean writeLock,
 int limit,
 int offset)

Description copied from interface: Backend

Creates a select statement string from an inner sql string.

sqlBuilder is anything as [SELECT] FROM... WHERE... ORDER BY....
It is decorated with a leading SELECT, if missing, plus optional clauses like for the given parameters.

Specified by:

buildSelectSql in interface Backend

Overrides:

buildSelectSql in class AbstractSql92Backend

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

setLeadingSelectParameters

public int setLeadingSelectParameters(BackendPreparedStatement stmt,
 int limit,
 int offset)

Description copied from interface: Backend

Sets optional parameters before applying the original parameters.

Specified by:

setLeadingSelectParameters in interface Backend

Overrides:

setLeadingSelectParameters in class AbstractSql92Backend

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

public int setTrailingSelectParameters(BackendPreparedStatement stmt,
 int index,
 int limit,
 int offset)

Description copied from interface: Backend

Sets optional parameters after applying the original parameters.

Specified by:

setTrailingSelectParameters in interface Backend

Overrides:

setTrailingSelectParameters in class AbstractSql92Backend

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

createColumnMetaData

public ColumnMetaData createColumnMetaData(TableMetaData tableMetaData)

Description copied from interface: Backend

Creates a column meta data instance.

Specified by:

createColumnMetaData in interface Backend

Overrides:

createColumnMetaData in class AbstractBackend

Parameters:

tableMetaData - the table metadata this column belongs to

Returns:

the meta data

createIndexMetaData

public IndexMetaData createIndexMetaData(TableMetaData tableMetaData)

Description copied from interface: Backend

Creates an index meta data instance.

Specified by:

createIndexMetaData in interface Backend

Overrides:

createIndexMetaData in class AbstractBackend

Parameters:

tableMetaData - the table metadata this index belongs to

Returns:

the meta data

createIndexColumnMetaData

public IndexColumnMetaData createIndexColumnMetaData(IndexMetaData indexMetaData)

Description copied from interface: Backend

Creates an index column meta data instance.

Specified by:

createIndexColumnMetaData in interface Backend

Overrides:

createIndexColumnMetaData in class AbstractBackend

Parameters:

indexMetaData - the meta meta data this column belongs to

Returns:

the meta data

getMaxSize

public int getMaxSize(SqlType sqlType)

Description copied from interface: Backend

Returns the maximum size for a given SQL-type.

Specified by:

getMaxSize in interface Backend

Overrides:

getMaxSize in class AbstractBackend

Parameters:

sqlType - the SQL-type

Returns:

the maximum size, 0 if unlimited, -1 if type without size

getDefaultSize

public int getDefaultSize(SqlType sqlType)

Description copied from interface: Backend

Gets the default size if no size given in model.

Specified by:

getDefaultSize in interface Backend

Overrides:

getDefaultSize in class AbstractBackend

Parameters:

sqlType - the SQL-type

Returns:

the default size, 0 if no default size

getDefaultSchema

public String getDefaultSchema()

Description copied from interface: Backend

Gets the default schema name.
Some backends store the objects in a default schema, if no explicit schema is given.

Specified by:

getDefaultSchema in interface Backend

Overrides:

getDefaultSchema in class AbstractBackend

Returns:

the default schema, null if none

jdbcTypeToSqlType

public SqlType[] jdbcTypeToSqlType(int jdbcType,
 int size,
 int scale)

Description copied from interface: Backend

Converts the JDBC data type integer to a tentackle backend SqlTypes.

There may be more than one sqltype returned!

Specified by:

jdbcTypeToSqlType in interface Backend

Overrides:

jdbcTypeToSqlType in class AbstractBackend

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

sqlTypeToString

public String sqlTypeToString(SqlType sqlType,
 int size)

Description copied from interface: Backend

Converts the java SQL-type to the database type name.

Specified by:

sqlTypeToString in interface Backend

Overrides:

sqlTypeToString in class AbstractBackend

Parameters:

sqlType - the java sql type

size - the column's size

Returns:

the corresponding type string

isSequenceSupported

public boolean isSequenceSupported()

Description copied from interface: Backend

True if backend provides locking-free sequences.
Sequences must not take part in transactions, i.e. no read- or write-locks!

Specified by:

isSequenceSupported in interface Backend

Overrides:

isSequenceSupported in class AbstractSql92Backend

Returns:

true if database supports sequences

sqlNextFromSequence

public String sqlNextFromSequence(String name)

Description copied from interface: Backend

Creates the SQL string to retrieve the next id from a sequence.

Specified by:

sqlNextFromSequence in interface Backend

Overrides:

sqlNextFromSequence in class AbstractSql92Backend

Parameters:

name - the name of the sequence

Returns:

the SQL code

sqlCreateSequence

public String sqlCreateSequence(String name,
 Long start,
 Long increment)

Description copied from interface: Backend

Creates the SQL string to create a sequence.

Specified by:

sqlCreateSequence in interface Backend

Overrides:

sqlCreateSequence in class AbstractSql92Backend

Parameters:

name - the sequence name

start - the optional start value, defaults to 1

increment - the optional increment, defaults to 1

Returns:

the SQL code

sqlCreateSequenceComment

public String sqlCreateSequenceComment(String name,
 String comment)

Description copied from interface: Backend

Creates the SQL string to comment a sequence.

Specified by:

sqlCreateSequenceComment in interface Backend

Overrides:

sqlCreateSequenceComment in class AbstractSql92Backend

Parameters:

name - the sequence name

comment - the comment

Returns:

the SQL code

sqlCreateTableComment

public String sqlCreateTableComment(String tableName,
 String comment)

Description copied from interface: Backend

Generates SQL code to create the comment for a table.

Specified by:

sqlCreateTableComment in interface Backend

Overrides:

sqlCreateTableComment in class AbstractBackend

Parameters:

tableName - the table name

comment - optional comment, null if none

Returns:

the SQL code, empty string if comment is created via Backend.sqlCreateTableIntro(java.lang.String, java.lang.String) or Backend.sqlCreateTableClosing(java.lang.String, java.lang.String)

sqlCreateColumnComment

public String sqlCreateColumnComment(String tableName,
 String columnName,
 String comment)

Description copied from interface: Backend

Generates SQL code to create the comment for an attribute.

Specified by:

sqlCreateColumnComment in interface Backend

Overrides:

sqlCreateColumnComment in class AbstractBackend

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 Backend.sqlCreateColumn(java.lang.String, java.lang.String, org.tentackle.sql.SqlType, int, int, boolean, java.lang.Object, boolean, boolean)

sqlAlterColumnType

public String sqlAlterColumnType(String tableName,
 String columnName,
 String comment,
 SqlType sqlType,
 int size,
 int scale,
 boolean nullable,
 Object defaultValue)

Description copied from interface: Backend

Generates sql code to change the datatype of a column.

Specified by:

sqlAlterColumnType in interface Backend

Overrides:

sqlAlterColumnType in class AbstractBackend

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

sqlAlterColumnNullConstraint

public String sqlAlterColumnNullConstraint(String tableName,
 String columnName,
 boolean nullable)

Description copied from interface: Backend

Generates sql code to change the null-constraint of a column.

Specified by:

sqlAlterColumnNullConstraint in interface Backend

Overrides:

sqlAlterColumnNullConstraint in class AbstractBackend

Parameters:

tableName - the tablename

columnName - the new column name

nullable - true if NULL, else NOT NULL

Returns:

the SQL code, null if need Backend.sqlAlterColumnType(java.lang.String, java.lang.String, java.lang.String, org.tentackle.sql.SqlType, int, int, boolean, java.lang.Object)

toInternalType

public String toInternalType(String sqlTypeName)

Description copied from interface: Backend

Converts a backend specific type name to an internal name used by driver specific methods.

Specified by:

toInternalType in interface Backend

Overrides:

toInternalType in class AbstractBackend

Parameters:

sqlTypeName - the original type used in SQL scripts

Returns:

the JDBC internal name

isArrayOperatorSupported

public boolean isArrayOperatorSupported(String operator)

Description copied from interface: Backend

Returns whether the backend supports given array operator.

Specified by:

isArrayOperatorSupported in interface Backend

Overrides:

isArrayOperatorSupported in class AbstractBackend

Parameters:

operator - the array operator

Returns:

true if supported

getMigrationStrategy

public MigrationStrategy[] getMigrationStrategy(ColumnMetaData column,
 String columnName,
 String comment,
 SqlType sqlType,
 int size,
 int scale,
 boolean nullable,
 Object defaultValue)

Description copied from interface: Backend

Determines the best migration strategy.

Specified by:

getMigrationStrategy in interface Backend

Overrides:

getMigrationStrategy in class AbstractBackend

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

createScriptRunner

public ScriptRunner createScriptRunner(Connection connection)

Description copied from interface: Backend

Creates a script runner instance.

Specified by:

createScriptRunner in interface Backend

Overrides:

createScriptRunner in class AbstractBackend

Parameters:

connection - the SQL-connection

extractWhereClause

protected String extractWhereClause(String sql,
 int whereOffset)

Description copied from class: AbstractBackend

Extracts the where clause from a given sql.

Overrides:

extractWhereClause in class AbstractBackend

Parameters:

sql - the sql statement

whereOffset - the location of WHERE in sql

Returns:

the where clause without the keyword WHERE

isDropIfExistsSupported

protected boolean isDropIfExistsSupported()

Description copied from class: AbstractBackend

Adds "IF EXISTS" to drop clauses, if supported by the backend.
Makes migration a little more robust in case the same SQL scripts are applied to different databases than those used to generate the migration scripts for.

Overrides:

isDropIfExistsSupported in class AbstractBackend

Returns:

true if supported