low level table operations moved to separate routine

Ignore-this: be0109b9771cb2b8ec28491b8d3154bc

darcs-hash:20110416000432-067c0-c8a54be0240ab9773121708e65d8835d6a769535.gz

1 files changed, 74 insertions, 0 deletions

diff --git a/libBasicTableOperations.tcl b/libBasicTableOperations.tcl
new file mode 100755
index 0000000..4eca8c8
--- /dev/null
+++ b/libBasicTableOperations.tcl
@@ -0,0 +1,74 @@
+#!/bin/sh
+# FILE: "/home/evmik/src/my_src/GradeBook/libBasicTableOperations.tcl"
+# LAST MODIFICATION: "Fri, 15 Apr 2011 20:01:22 -0400 (evmik)"
+# (C) 2011 by Eugeniy Mikhailov, <evgmik@gmail.com>
+# $Id:$
+# vim:set ft=tcl: \
+exec tclsh "$0" "$@"
+
+# #######################################################
+# everywhere below db must be initialized with command
+#	sqlite3 db $dbfile
+# #######################################################
+
+proc getColListFromTable {table} {
+	set eval_str [concat SELECT * FROM \'$table\']
+	set err [catch {
+		db eval $eval_str v {
+			set all_column_names $v(*)
+			}
+		} errStat ]
+		if { $err } {
+			dbg "we should never be here if GradesTable exists" 1
+			dbg $errStat 1
+			htmlErrorMsg $errStat
+		}
+	return $all_column_names	
+}
+
+proc SelectColvalueFromTable { table  column_of_interest col row_value } {
+	# select value of 'column_of_interest' from 'table' where 'col'='row_value'
+	set value {}
+	set eval_str "SELECT \"$column_of_interest\"  FROM \'$table\'  WHERE \"$col\"=\"$row_value\""
+	set err [catch {
+		db eval $eval_str v {
+			set value $v($column_of_interest)
+		}
+	} errStat ]
+	if { $err } {
+		set msg_text "the following error happen in proc SelectColvalueFromTable while selecting from table $table $errStat"
+		htmlErrorMsg  $msg_text
+		dbg  $msg_text 3
+		set $value {}
+	} 
+	return $value
+}
+
+proc existsColumnWithRowvalueInTable { table column row_value } {
+	set sql_str [concat SELECT 1 FROM \'$table\'  WHERE \"$column\"=\"$row_value\"]
+	if {![db exists $sql_str]} {
+		dbg  "Column \'$column\' does not have row with value \'$row_value\' in table \'$table\'" 3
+		return false
+	} else {
+		return true
+	}
+}
+
+proc UpdateColumnWithValueInTableWhere { table column val where_column row_value } {
+	set eval_str [concat UPDATE \'$table\' SET \"$column\"='$val' WHERE \"$where_column\"=\'$row_value\']
+	set err [catch {db eval $eval_str  } errStat]
+	if { $err } {
+		set msg_str  "Unable to update column $column in the table $table where $where_column=$row_value. The following error happen: $errStat" 
+		htmlErrorMsg  $msg_str
+		dbg  $msg_str 3
+	} 
+}
+
+proc doesColumnExists {col  table} {
+	if { $col in [getColListFromTable $table] } { 
+		return true;
+	} else {
+		return false;
+	}
+}
+