%SQL.FDW.Wrapper.CsvWrapper

Inherited description: All foreign data wrappers should define an %OnNew() method that will accept a JSON config object containing relevant information for that wrapper to perform its intended behavior based on a given foreign server and foreign table. Upon wrapper construction, the wrapper should be in a state that is sufficient to call execute() and to provide metadata via the getMetadata() method. Note that the actual metadata does not need to be fetched until getMetadata() is called, but that the wrapper should be prepared to do so upon execution without any other interaction from the caller. The wrapper config object conforms to the following format. The types listed are JSON types. For more information about manipulating this object, see %Library.DynamicAbstractObject. { "server": { "connection": string, corresponds to CONNECTION parameter the foreign server was created with. "delimitedIds": boolean, corresponds to DELIMITEDIDS parameter the foreign server was created with. "fdwName": string, name of the %SQL.FDW.Wrapper.BaseWrapper subclass that this server was intended to be used with. "host": string, corresponds to HOST parameter the foreign server was created with. "passthrough": boolean, corresponds to [ ENABLE | DISABLE ] PASSTHROUGH setting the foreign server was created with and specifies whether the server supports the PASSTHROUGH feature. "pushdownType": string, if this wrapper is a subclass of %SQL.FDW.Wrapper.SqlWrapper, this setting corresponds to the PUSHDOWN setting the foreign server was created with. "using": object, corresponds to the USING parameter the foreign server was created with, which can be used to specify any arbitrary table parameters your wrapper might need to function. }, Note that this is a JSON array of tables involved in this wrapper. For example, this may be populated with multiple tables if pushdown logic decided to combine multiple tables into one pushdown unit. "tables": [ { "columns": array, corresponds to the COLUMNS parameter the foreign table was created with. This only applies to CSV foreign tables and is used to specify a custom header row. "columnsTypes": array, names of datatypes corresponding to the indices in the columns array above. This only applies to CSV foreign tables. "values": array, corresponds to the VALUES parameter the foreign table was created with (i.e. external column names.) "query": string, corresponds to the QUERY parameter the foreign table was created with. "table": string, corresponds to the TABLE parameter the foreign table was created with. Note that for foreign tables created under a foreign server that utilizes %SQL.FDW.Wrapper.CsvWrapper, this field contains the value entered for the FILE parameter upon creation of the foreign table. "using": object, corresponds to the USING parameter the foreign table was created with, which can be used to specify any arbitrary table parameters your wrapper might need to function. }, ], "sql": string, specifies the SQL text determined via internal pushdown logic. This logic is only performed during SQL query execution for foreign tables that belong to servers using wrappers that extend the %SQL.FDW.Wrapper.SqlWrapper class. "sqlParameters": array, containing subarrays of the format [type, value] where each subarray corresponds positionally to a ? parameter in the config.sql parameter. The type is an integer corresponding to ODBC type numbers. For more information, see the %SQL.FDW.Wrapper.SqlWrapper class. }

Close up the gateway objects/connection

No-op for CSV

Inherited description: Get the value at column index columnIndex for the current row. This should match the value in row(columnIndex). If the

Inherited description: Creates and returns an instance of %SQL.FDW.Metadata.ResultMetadata, which describes the result being returned by this wrapper. For more information on the metadata object, see the %SQL.FDW.Metadata.ResultMetadata class.

Build and return request string used by Reader code for connecting to a database. For a file, Server host = abs. path to directory, Table = filename+extension, port & user & pass are all N/A

Inherited description: The next() advances the wrapper to the next row. If such a row is found, this method returns 1. If no additional row is found, this method returns 0. This method should always populate the multidimensional row property with the current row's data in the structure of row(columnIndex) = value.

Inherited description: Resets the result set being looped over by the wrapper, effectively positioning the pointer before the first row again. The wrapper API places no constraint on how this is done. For example, this method may require cleaning up all resources and executing from the beginning; that is an implementation detail. Upon finishing reset(), the wrapper should be as though execute() was just called the first time. In other words, the wrapper should be prepared to loop over the result set that it projects, with the first next() call following the reset returning the first row. This method should return a %Status value. Consider using status code $$$ForeignDataWrapperError when reporting custom error status messages.

Inherited description: Given a %DynamicObject representing the server portion of a config object, validate that information contained in the object is sufficient for this wrapper to act upon. For example, if a wrapper requires the server to specify a "host" key, this method should validate that the serialized server information contains a relevant value: This method should return a %Status value. Consider using status code $$$ForeignDataWrapperError when reporting custom error status messages.

Inherited description: Given a %DynamicObject representing one table in the "tables" portion of a JSON config object, validate that information contained in the object is sufficient for this wrapper to act upon. For example, if a wrapper requires the tables to specify "table", this method should validate that the serialized table information contains a relevant value. This method should return a %Status value. Consider using status code $$$ForeignDataWrapperError when reporting custom error status messages.

OVERRIDE METHOD - require size of 1