com.opengamma.elsql
Class ElSqlConfig

java.lang.Object
  com.opengamma.elsql.ElSqlConfig

public class ElSqlConfig
extends Object

Configuration that provides support for differences between databases.

The class provides SQL fragments that the tags use to build the complete SQL. Some standard implementations have been provided, but subclasses may be added.

Implementations must be thread-safe.

DEFAULT

public static final ElSqlConfig DEFAULT

A constant for the standard set of config, based on ANSI SQL.

POSTGRES

public static final ElSqlConfig POSTGRES

A constant for the config needed for Postgres, the same as DEFAULT.

HSQL

public static final ElSqlConfig HSQL

A constant for the config needed for HSQL, which escapes the LIKE clause.

MYSQL

public static final ElSqlConfig MYSQL

A constant for the config needed for MySQL, which uses LIMIT-OFFSET instead of FETCH-OFFSET.

ORACLE

public static final ElSqlConfig ORACLE

A constant for the config needed for Oracle RDBMS.

SQL_SERVER_2008

public static final ElSqlConfig SQL_SERVER_2008

A constant for the config needed for SQL Server 2008, which pages in a different way.

VERTICA

public static final ElSqlConfig VERTICA

A constant for the config needed for Vertica, the same as DEFAULT.

ElSqlConfig

public ElSqlConfig(String name)

Creates an instance.

Parameters:

name - a descriptive name for the config, not null

getName

public final String getName()

Gets the config name.

Returns:

the config name, not null

isLikeWildcard

public boolean isLikeWildcard(String value)

Checks if the value contains a wildcard.

The default implementation matches % and _, using backslash as an escape character. This matches Postgres and other databases.

Parameters:

value - the value to check, not null

Returns:

true if the value contains wildcards

getLikeSuffix

public String getLikeSuffix()

Gets the suffix to add after LIKE, which would typically be an ESCAPE clause.

The default implementation returns an empty string. This matches Postgres and other databases.

The returned SQL must be end in a space if non-empty.

Returns:

the suffix to add after LIKE, not null

addPaging

public String addPaging(String selectToPage,
                        int offset,
                        int fetchLimit)

Alters the supplied SQL to add paging, such as OFFSET-FETCH.

The default implementation calls getPaging(int, int).

The returned SQL must be end in a space if non-empty.

Parameters:

selectToPage - the SELECT statement to page, not null

offset - the OFFSET amount, zero to start from the beginning

fetchLimit - the FETCH/LIMIT amount, zero to fetch all

Returns:

the updated SELECT, not null

getPaging

public String getPaging(int offset,
                        int fetchLimit)

Gets the paging SQL, such as OFFSET-FETCH.

The default implementation uses 'FETCH FIRST n ROWS ONLY' or 'OFFSET n ROWS FETCH NEXT n ROWS ONLY'. This matches Postgres, HSQL and other databases.

The returned SQL must be end in a space if non-empty.

Parameters:

offset - the OFFSET amount, zero to start from the beginning

fetchLimit - the FETCH/LIMIT amount, zero to fetch all

Returns:

the SQL to use, not null

toString

public String toString()

Overrides:

toString in class Object