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Creating and Dropping CONNECT Tables

MariaDB starting with 10.0

The CONNECT handler was introduced in MariaDB 10.0.

Create Table statements for “CONNECT” tables are standard MariaDB create statements specifying engine=CONNECT. There are a few additional table and column options specific to CONNECT.

Table Options

Table Option Type Description
AVG_ROW_LENGTH Integer Can be specified to help CONNECT estimate the size of a variable record table length.
BLOCK_SIZE Integer The number of rows each block of a FIX, BIN, DBF, or VEC table contains. For an ODBC table this is the RowSet size option. For a JDBC table this is the fetch size.
CATFUNC String The catalog function used by a catalog table.
COLIST String The column list of OCCUR tables or $project of MONGO tables.
COMPRESS Number 1 or 2 if the data file is g-zip compressed. Defaults to 0. Before CONNECT 1.05.0001, this was boolean, and true if the data file is compressed.
CONNECTION String Specifies the connection of an ODBC, JDBC or MYSQL table.
DATA_CHARSET String The character set used in the external file or data source.
DBNAME String The target database for ODBC, JDBC, MYSQL, catalog, and PROXY based tables. The database concept is sometimes known as a schema.
ENGINE String Must be specfied as CONNECT.
ENDING Integer End of line length. Defaults to 1 for Unix/Linux and 2 for Windows.
FILE_NAME String The file (path) name for all table types based on files. Can be absolute or relative to the current data directory. If not specified, this is an Inward table and a default value is used.
FILTER String To filter an external table. Currently MONGO tables only.
HEADER Integer Applies to CSV, VEC, and HTML files. Its meaning depends on the table type.
HTTP String The HTTP of the client of REST queries. From Connect 1.06.0010.
HUGE Boolean To specify that a table file can be larger than 2GB. For a MYSQL table, prevents the result set from being stored in memory.
LRECL Integer The file record size (often calculated by default).
MAPPED Boolean Specifies whether file mapping is used to handle the table file.
MODULE String The (path) name of the DLL or shared lib implementing the access of a non-standard (OEM) table type.
MULTIPLE Integer Used to specify multiple file tables.
OPTION_LIST String Used to specify all other options not yet directly defined.
QCHAR String Specifies the character used for quoting some fields of a CSV table or the identifiers of an ODBC/JDBC tables.
QUOTED Integer The level of quoting used in CSV table files.
READONLY Boolean True if the data file must not be modified or erased.
SEP_CHAR String Specifies the field separator character of a CSV or XCOL table. Also, used to specify the Jpath separator for JSON tables.
SEPINDEX Boolean When true, indexes are saved in separate files.
SPLIT Boolean True for a VEC table when all columns are in separate files.
SRCDEF String The source definition of a table retrieved via ODBC, JDBC or the MySQL API or used by a PIVOT table.
SUBTYPE String The subtype of an OEM table type.
TABLE_LIST String The comma separated list of TBL table sub-tables.
TABLE_TYPE String The external table type: DOS, FIX, BIN, CSV, FMT, XML, JSON, INI, DBF, VEC, ODBC, JDBC, MYSQL, TBL, PROXY, XCOL, OCCUR, PIVOT, ZIP, VIR, DIR, WMI, MAC, and OEM. Defaults to DOS, MYSQL, or PROXY depending on what options are used.
TABNAME String The target table or node for ODBC, JDBC, MYSQL, PROXY, or catalog tables; or the top node name for XML tables.
URI String The URI of a REST request.. From Connect 1.06.0010.
XFILE_NAME String The file (path) base name for table index files. Can be absolute or relative to the data directory. Defaults to the file name.
ZIPPED Boolean True if the table file(s) is/are zipped in one or several zip files.

All integers in the above table are unsigned big integers.

Because CONNECT handles many table types; many table type specific options are not in the above list and must be entered using the OPTION_LIST option. The syntax to use is:

... option_list='opname1=opvalue1,opname2=opvalue2...'

Be aware that until Connect 1.5.5, no blanks should be inserted before or after the '=' and ',' characters. The option name is all that is between the start of the string or the last ',' character and the next '=' character, and the option value is all that is between this '=' character and the next ',' or end of string. For instance:

option_list='name=TABLE,coltype=HTML,attribute=border=1;cellpadding=5,headattr=bgcolor=yellow';

This defines four options, 'name', 'coltype', 'attribute', and 'headattr'; with values 'TABLE', 'HTML', 'border=1;cellpadding=5', and 'bgcolor=yellow', respectively. The only restriction is that values cannot contain commas, but they can contain equal signs.

Column Options

Column Option Type Description
DATE_FORMAT String The format indicating how a date is stored in the file.
DISTRIB Enum “scattered”, “clustered”, “sorted” (ascending).
FIELD_FORMAT String The column format for some table types.
FIELD_LENGTH Integer Set the internal field length for DATE columns.
FLAG Integer An integer value whose meaning depends on the table type.
MAX_DIST Integer Maximum number of distinct values in this column.
SPECIAL String The name of the SPECIAL column that set this column value.
  • The MAX_DIST and DISTRIB column options are used for block indexing.
  • All integers in the above table are unsigned big integers.

Index Options

Index Option Type Description
DYNAM Boolean Set the index as “dynamic”.
MAPPED Boolean Use index file mapping.

Note 1: Creating a CONNECT table based on file does not erase or create the file if the file name is specified in the CREATE TABLE statement (“outward” table). If the file does not exist, it will be populated by subsequent INSERT or LOAD commands or by the “AS select statement” of the CREATE TABLE command. Unlike the CSV engine, CONNECT easily permits the creation of tables based on already existing files, for instance files made by other applications. However, if the file name is not specified, a file with a name defaulting to tablename.tabletype will be created in the data directory (“inward” table).

Note 2: Dropping a CONNECT table is done with a standard DROP statement. For outward tables, this drops only the CONNECT table definition but does not erase the corresponding data file and index files. Use DELETE or TRUNCATE to do so. This is contrary to data and index files of inward tables are erased on DROP like for other MariaDB engines.

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https://mariadb.com/kb/en/creating-and-dropping-connect-tables/