Feature/default value

schema/schema.go

@@ -49,12 +49,13 @@ type Table struct {
 // Column represents a database column.
 // TODO: add support for foreign keys.
 type Column struct {
-	Name    	string
-	Type    	Type
-	NotNull 	bool
-	Ignored 	Ignored
-	Id      	string
-	AutoGen		ddl.AutoGenCol
+	Name         string
+	Type         Type
+	NotNull      bool
+	Ignored      Ignored
+	Id           string
+	AutoGen      ddl.AutoGenCol
+	DefaultValue DefaultValue
 }
 
 // ForeignKey represents a foreign key.
@@ -122,6 +123,12 @@ type Ignored struct {
 	AutoIncrement bool
 }
 
+// DefaultValue represents a Default value.
+type DefaultValue struct {
+	IsPresent bool
+	Value     string
+}
+
 // Print converts ty to a string suitable for printing.
 func (ty Type) Print() string {
 	s := ty.Name

sources/mysql/infoschema.go

@@ -204,7 +204,7 @@ func (isi InfoSchemaImpl) GetColumns(conv *internal.Conv, table common.SchemaAnd
 				// Nothing to do here -- these are all handled elsewhere.
 			}
 		}
-		ignored.Default = colDefault.Valid
+		ignored.Default = false
 		colId := internal.GenerateColumnId()
 		if colExtra.String == "auto_increment" {
 			sequence := createSequence(conv)
@@ -219,20 +219,48 @@ func (isi InfoSchemaImpl) GetColumns(conv *internal.Conv, table common.SchemaAnd
 		} else {
 			colAutoGen = ddl.AutoGenCol{}
 		}
+		defaultVal := schema.DefaultValue{
+			IsPresent: colDefault.Valid,
+			Value:     "",
+		}
+		if colDefault.Valid {
+			defaultVal.Value = sanitizeDefaultValue(colDefault.String)
+		}
+
 		c := schema.Column{
-			Id:      colId,
-			Name:    colName,
-			Type:    toType(dataType, columnType, charMaxLen, numericPrecision, numericScale),
-			NotNull: common.ToNotNull(conv, isNullable),
-			Ignored: ignored,
-			AutoGen: colAutoGen,
+			Id:           colId,
+			Name:         colName,
+			Type:         toType(dataType, columnType, charMaxLen, numericPrecision, numericScale),
+			NotNull:      common.ToNotNull(conv, isNullable),
+			Ignored:      ignored,
+			AutoGen:      colAutoGen,
+			DefaultValue: defaultVal,
 		}
 		colDefs[colId] = c
 		colIds = append(colIds, colId)
 	}
 	return colDefs, colIds, nil
 }
 
+// sanitizeDefaultValue removes extra characters added to Default Value in information schema in MySQL.
+// Example_1:
+// Default Value: "concat('John', 'swamp', 'span')"
+// Default Value in MySQL infoschema with extra characters: "concat(_utf8mb4\\'John\\',_utf8mb4\\'swamp\\',_utf8mb4\\'span\\')"
+// Default Value after removing "_utf8mb4": "concat( \\'John\\',  \\'swamp\\',  \\'span\\')"
+// Default Value after removing all backslashes: "concat('John','swamp','span')"
+// Example_2:
+// Default Value: "This is a message \nwith a newline\rand a carriage return."
+// Default Value in MySQL infoschema with extra characters: "_utf8mb4\\'This is a \\tmessage \\\\nwith a newline\\\\\\'s and \\\\ra carriage return.\\'"
+// Default Value after removing "_utf8mb4": " \\'This is a \\tmessage \\\\nwith a newline\\\\\\'s and \\\\ra carriage return.\\'"
+// Default Value after removing all "\\\\": " \\'This is a \\tmessage \\nwith a newline\\\\'s and \\ra carriage return.\\'
+// Default Value after removing all "\\'": "'This is a 	message \\nwith a newline\\'s \\rand a carriage return.'
+func sanitizeDefaultValue(defaultValue string) string {
+	defaultValue = strings.ReplaceAll(defaultValue, "_utf8mb4", " ")
+	defaultValue = strings.ReplaceAll(defaultValue, "\\\\", "\\")
+	defaultValue = strings.ReplaceAll(defaultValue, "\\'", "'")
+	return defaultValue
+}
+
 // GetConstraints returns a list of primary keys and by-column map of
 // other constraints.  Note: we need to preserve ordinal order of
 // columns in primary key constraints.