/**

• Constructor
• @param int $uniqueid all tables have to have a unique id, this is used
• as a key when storing table properties like sort order in the session.
  */

If you find usages, it is easy to spot it requires a string.

admin/reports.php:43:$table = new flexible_table('reportplugins_administration_table');
admin/tool/availabilityconditions/index.php:71:$table = new flexible_table('availabilityconditions_administration_table');
admin/tool/recyclebin/index.php:163:$table = new flexible_table('recyclebin');
admin/qtypes.php:131:$table = new flexible_table('qtypeadmintable');
admin/localplugins.php:41:$table = new flexible_table('localplugins_administration_table');
admin/modules.php:82: $table = new flexible_table(MODULE_TABLE);
admin/blocks.php:97: $table = new flexible_table('admin-blocks-compatible');
admin/blocks.php:227: $table = new flexible_table('admin-blocks-incompatible');
admin/qbehaviours.php:147:$table = new flexible_table('qbehaviouradmintable');
admin/tools.php:43:$table = new flexible_table('toolplugins_administration_table');
report/participation/index.php:173: $table = new flexible_table('course-participation-'.$course->id.''.$cm>id.'-'.$roleid);
mod/feedback/show_nonrespondents.php:164:$table = new flexible_table('feedback-shownonrespondents-'.$course->id);
mod/scorm/report/userreporttracks.php:94:$table = new flexible_table('mod_scorm-userreporttracks');
mod/scorm/report/userreportinteractions.php:82:$table = new flexible_table('mod-scorm-userreport-interactions');
mod/assign/adminlib.php:177: $table = new flexible_table($this->subtype . 'pluginsadminttable');
grade/report/overview/lib.php:154: $this->table = new flexible_table('grade-report-overview-'.$this->user->id);
lib/tests/tablelib_test.php:104: $table = new flexible_table('tablelib_test');
lib/tests/tablelib_test.php:361: $table = new flexible_table('tablelib_test');
lib/tests/tablelib_test.php:380: $table1 = new flexible_table('tablelib_test');
lib/tests/tablelib_test.php:402: $table2 = new flexible_table('tablelib_test');
lib/tests/tablelib_test.php:423: $table3 = new flexible_table('tablelib_test');
lib/tests/tablelib_test.php:444: $table4 = new flexible_table('tablelib_test');
lib/tests/tablelib_test.php:465: $table5 = new flexible_table('tablelib_test');
lib/tests/tablelib_test.php:484: $table6 = new flexible_table('tablelib_test');
blocks/rss_client/managefeeds.php:91:$table = new flexible_table('rss-display-feeds');
user/index.php:376:$table = new flexible_table('user-index-participants-'.$course->id);