Support column comments (#32)

* support column comments for mysql

* support column comments for postgres

* support column comments for mssql

* add tests for column comment support

* add support for combining enumValues and columnComments

* fix typo

cmd/root.go

@@ -69,13 +69,13 @@ func init() {
 	rootCmd.Flags().Bool(config.DebugKey, false, "show debug logs")
 	rootCmd.Flags().Bool(config.OmitConstraintLabelsKey, false, "omit the constraint labels")
 	rootCmd.Flags().Bool(config.OmitAttributeKeysKey, false, "omit the attribute keys (PK, FK)")
-	rootCmd.Flags().Bool(config.ShowEnumValuesKey, false, "show enum values in description column")
 	rootCmd.Flags().Bool(config.ShowSchemaPrefix, false, "show schema prefix in table name")
 	rootCmd.Flags().BoolP(config.EncloseWithMermaidBackticksKey, "e", false, "enclose output with mermaid backticks (needed for e.g. in markdown viewer)")
 	rootCmd.Flags().StringP(config.ConnectionStringKey, "c", "", "connection string that should be used")
 	rootCmd.Flags().StringP(config.SchemaKey, "s", "", "schema that should be used")
 	rootCmd.Flags().StringP(config.OutputFileNameKey, "o", "result.mmd", "output file name")
 	rootCmd.Flags().String(config.SchemaPrefixSeparator, ".", "the separator that should be used between schema and table name")
+	rootCmd.Flags().StringSlice(config.ShowDescriptionsKey, []string{""}, "show 'enumValues' and/or 'columnComments' in the description column")
 	rootCmd.Flags().StringSlice(config.SelectedTablesKey, []string{""}, "tables to include")
 
 	bindFlagToViper(config.ShowAllConstraintsKey)
@@ -89,7 +89,7 @@ func init() {
 	bindFlagToViper(config.SchemaKey)
 	bindFlagToViper(config.OutputFileNameKey)
 	bindFlagToViper(config.SelectedTablesKey)
-	bindFlagToViper(config.ShowEnumValuesKey)
+	bindFlagToViper(config.ShowDescriptionsKey)
 	bindFlagToViper(config.ShowSchemaPrefix)
 	bindFlagToViper(config.SchemaPrefixSeparator)
 }

config/config.go

@@ -14,7 +14,7 @@ const (
 	DebugKey                       = "debug"
 	OmitConstraintLabelsKey        = "omitConstraintLabels"
 	OmitAttributeKeysKey           = "omitAttributeKeys"
-	ShowEnumValuesKey              = "showEnumValues"
+	ShowDescriptionsKey            = "showDescriptions"
 	UseAllSchemasKey               = "useAllSchemas"
 	ShowSchemaPrefix               = "showSchemaPrefix"
 	SchemaPrefixSeparator          = "schemaPrefixSeparator"
@@ -34,7 +34,7 @@ type MermerdConfig interface {
 	Debug() bool
 	OmitConstraintLabels() bool
 	OmitAttributeKeys() bool
-	ShowEnumValues() bool
+	ShowDescriptions() []string
 	UseAllSchemas() bool
 	ShowSchemaPrefix() bool
 	SchemaPrefixSeparator() string
@@ -88,8 +88,8 @@ func (c config) OmitAttributeKeys() bool {
 	return viper.GetBool(OmitAttributeKeysKey)
 }
 
-func (c config) ShowEnumValues() bool {
-	return viper.GetBool(ShowEnumValuesKey)
+func (c config) ShowDescriptions() []string {
+	return viper.GetStringSlice(ShowDescriptionsKey)
 }
 
 func (c config) UseAllSchemas() bool {

config/config_test.go

@@ -28,7 +28,9 @@ encloseWithMermaidBackticks: false
 debug: true
 omitConstraintLabels: true
 omitAttributeKeys: true
-showEnumValues: true
+showDescriptions:
+  - enumValues
+  - columnComments
 useAllSchemas: true
 showSchemaPrefix: true
 schemaPrefixSeparator: "_"
@@ -56,7 +58,7 @@ connectionStringSuggestions:
 	assert.True(t, config.Debug())
 	assert.True(t, config.OmitConstraintLabels())
 	assert.True(t, config.OmitAttributeKeys())
-	assert.True(t, config.ShowEnumValues())
+	assert.ElementsMatch(t, []string{"enumValues", "columnComments"}, config.ShowDescriptions())
 	assert.True(t, config.UseAllSchemas())
 	assert.True(t, config.ShowSchemaPrefix())
 	assert.Equal(t, "_", config.SchemaPrefixSeparator())

database/mssql.go

@@ -101,7 +101,11 @@ func (c *mssqlConnector) GetColumns(tableName TableDetail) ([]ColumnResult, erro
 						 left join information_schema.table_constraints tc on tc.constraint_name = cu.constraint_name
 				where cu.column_name = c.column_name
 				  and cu.table_name = c.table_name
-				  and tc.constraint_type = 'FOREIGN KEY') as is_foreign
+				  and tc.constraint_type = 'FOREIGN KEY') as is_foreign,
+			   (select ISNULL(ep.value, '') from sys.tables t
+			      inner join sys.columns col on col.object_id = t.object_id and col.name = c.column_name
+				  left join sys.extended_properties ep on ep.major_id = t.object_id and ep.minor_id = col.column_id
+				  where t.name = c.table_name and SCHEMA_NAME(t.schema_id) = c.TABLE_SCHEMA) as comment
 		from information_schema.columns c
 		where c.table_name = @p1 and c.TABLE_SCHEMA = @p2
 		order by c.ordinal_position;
@@ -113,7 +117,7 @@ func (c *mssqlConnector) GetColumns(tableName TableDetail) ([]ColumnResult, erro
 	var columns []ColumnResult
 	for rows.Next() {
 		var column ColumnResult
-		if err = rows.Scan(&column.Name, &column.DataType, &column.IsPrimary, &column.IsForeign); err != nil {
+		if err = rows.Scan(&column.Name, &column.DataType, &column.IsPrimary, &column.IsForeign, &column.Comment); err != nil {
 			return nil, err
 		}
 

database/mysql.go

@@ -99,7 +99,8 @@ func (c *mySqlConnector) GetColumns(tableName TableDetail) ([]ColumnResult, erro
 				where cu.column_name = c.column_name
 				  and cu.table_name = c.table_name
 				  and tc.constraint_type = 'FOREIGN KEY') as is_foreign,
-        case when c.data_type = 'enum' then REPLACE(REPLACE(REPLACE(REPLACE(c.column_type, 'enum', ''), '\'', ''), '(', ''), ')', '') else '' end as enum_values
+        case when c.data_type = 'enum' then REPLACE(REPLACE(REPLACE(REPLACE(c.column_type, 'enum', ''), '\'', ''), '(', ''), ')', '') else '' end as enum_values,
+		c.column_comment as comment
 		from information_schema.columns c
 		where c.table_name = ? and c.TABLE_SCHEMA = ?
 		order by c.ordinal_position;
@@ -111,7 +112,7 @@ func (c *mySqlConnector) GetColumns(tableName TableDetail) ([]ColumnResult, erro
 	var columns []ColumnResult
 	for rows.Next() {
 		var column ColumnResult
-		if err = rows.Scan(&column.Name, &column.DataType, &column.IsPrimary, &column.IsForeign, &column.EnumValues); err != nil {
+		if err = rows.Scan(&column.Name, &column.DataType, &column.IsPrimary, &column.IsForeign, &column.EnumValues, &column.Comment); err != nil {
 			return nil, err
 		}
 

database/postgres.go

@@ -101,16 +101,21 @@ func (c *postgresConnector) GetColumns(tableName TableDetail) ([]ColumnResult, e
                 where cu.column_name = c.column_name
                   and cu.table_name = c.table_name
                   and tc.constraint_type = 'FOREIGN KEY')                      as is_foreign,
-               coalesce(string_agg(enumlabel, ',' order by enumsortorder), '') as enum_values
+               coalesce(string_agg(enumlabel, ',' order by enumsortorder), '') as enum_values,
+               coalesce(pd.description, '')                   				   as comment
         from information_schema.columns c
                  left join pg_type typ on c.udt_name = typ.typname
                  left join pg_enum enu on typ.oid = enu.enumtypid
+                 left join pg_class cls on c.table_name = cls.relname
+				 left join pg_namespace ns on cls.relnamespace = ns.oid
+				 left join pg_description pd on cls.oid = pd.objoid and c.ordinal_position = pd.objsubid
         where c.table_name = $1  and c.table_schema = $2
         group by c.column_name,
                  c.table_name,
                  c.data_type,
                  c.udt_name,
-                 c.ordinal_position
+                 c.ordinal_position,
+         		 pd.description
         order by c.ordinal_position;
 		`, tableName.Name, tableName.Schema)
 	if err != nil {
@@ -120,7 +125,7 @@ func (c *postgresConnector) GetColumns(tableName TableDetail) ([]ColumnResult, e
 	var columns []ColumnResult
 	for rows.Next() {
 		var column ColumnResult
-		if err = rows.Scan(&column.Name, &column.DataType, &column.IsPrimary, &column.IsForeign, &column.EnumValues); err != nil {
+		if err = rows.Scan(&column.Name, &column.DataType, &column.IsPrimary, &column.IsForeign, &column.EnumValues, &column.Comment); err != nil {
 			return nil, err
 		}
 

database/result.go

@@ -21,6 +21,7 @@ type ColumnResult struct {
 	IsPrimary  bool
 	IsForeign  bool
 	EnumValues string
+	Comment    string
 }
 
 type ConstraintResultList []ConstraintResult

diagram/diagram_data.go

@@ -29,7 +29,7 @@ type ErdTableData struct {
 type ErdColumnData struct {
 	Name         string
 	DataType     string
-	EnumValues   string
+	Description  string
 	AttributeKey ErdAttributeKey
 }
 

diagram/diagram_util.go

@@ -2,6 +2,8 @@ package diagram
 
 import (
 	"fmt"
+	"github.com/sirupsen/logrus"
+	"strings"
 
 	"github.com/KarnerTh/mermerd/config"
 	"github.com/KarnerTh/mermerd/database"
@@ -43,19 +45,31 @@ func getColumnData(config config.MermerdConfig, column database.ColumnResult) Er
 		attributeKey = none
 	}
 
-	var enumValues string
-	if config.ShowEnumValues() {
-		enumValues = column.EnumValues
-	}
-
 	return ErdColumnData{
 		Name:         column.Name,
 		DataType:     column.DataType,
-		EnumValues:   enumValues,
+		Description:  getDescription(config.ShowDescriptions(), column),
 		AttributeKey: attributeKey,
 	}
 }
 
+func getDescription(options []string, column database.ColumnResult) string {
+	var description []string
+	for _, option := range options {
+		switch option {
+		case "enumValues":
+			if column.EnumValues != "" {
+				description = append(description, "<"+column.EnumValues+">")
+			}
+		case "columnComments":
+			description = append(description, column.Comment)
+		default:
+			logrus.Errorf("Could not parse option %q", option)
+		}
+	}
+	return strings.TrimSpace(strings.Join(description, " "))
+}
+
 func shouldSkipConstraint(config config.MermerdConfig, tables []ErdTableData, constraint database.ConstraintResult) bool {
 	if config.ShowAllConstraints() {
 		return false

diagram/diagram_util_test.go

@@ -128,73 +128,107 @@ func TestTableNameInSlice(t *testing.T) {
 func TestGetColumnData(t *testing.T) {
 	columnName := "testColumn"
 	enumValues := "a,b"
+	comment := "comment"
 	column := database.ColumnResult{
 		Name:       columnName,
 		IsPrimary:  true,
 		EnumValues: enumValues,
+		Comment:    comment,
 	}
 
 	t.Run("Get all fields", func(t *testing.T) {
 		// Arrange
 		configMock := mocks.MermerdConfig{}
 		configMock.On("OmitAttributeKeys").Return(false).Once()
-		configMock.On("ShowEnumValues").Return(true).Once()
+		configMock.On("ShowDescriptions").Return([]string{"enumValues", "columnComments"}).Once()
 
 		// Act
 		result := getColumnData(&configMock, column)
 
 		// Assert
 		configMock.AssertExpectations(t)
 		assert.Equal(t, columnName, result.Name)
-		assert.Equal(t, enumValues, result.EnumValues)
+		assert.Equal(t, "<"+enumValues+"> "+comment, result.Description)
 		assert.Equal(t, primaryKey, result.AttributeKey)
 	})
 
-	t.Run("Get all fields except enum values", func(t *testing.T) {
+	t.Run("Get all fields with enum values", func(t *testing.T) {
 		// Arrange
 		configMock := mocks.MermerdConfig{}
 		configMock.On("OmitAttributeKeys").Return(false).Once()
-		configMock.On("ShowEnumValues").Return(false).Once()
+		configMock.On("ShowDescriptions").Return([]string{"enumValues"}).Once()
 
 		// Act
 		result := getColumnData(&configMock, column)
 
 		// Assert
 		configMock.AssertExpectations(t)
 		assert.Equal(t, columnName, result.Name)
-		assert.Equal(t, "", result.EnumValues)
+		assert.Equal(t, "<"+enumValues+">", result.Description)
+		assert.Equal(t, primaryKey, result.AttributeKey)
+	})
+
+	t.Run("Get all fields with column comments", func(t *testing.T) {
+		// Arrange
+		configMock := mocks.MermerdConfig{}
+		configMock.On("OmitAttributeKeys").Return(false).Once()
+		configMock.On("ShowDescriptions").Return([]string{"columnComments"}).Once()
+
+		// Act
+		result := getColumnData(&configMock, column)
+
+		// Assert
+		configMock.AssertExpectations(t)
+		assert.Equal(t, columnName, result.Name)
+		assert.Equal(t, comment, result.Description)
+		assert.Equal(t, primaryKey, result.AttributeKey)
+	})
+
+	t.Run("Get all fields except description", func(t *testing.T) {
+		// Arrange
+		configMock := mocks.MermerdConfig{}
+		configMock.On("OmitAttributeKeys").Return(false).Once()
+		configMock.On("ShowDescriptions").Return([]string{""}).Once()
+
+		// Act
+		result := getColumnData(&configMock, column)
+
+		// Assert
+		configMock.AssertExpectations(t)
+		assert.Equal(t, columnName, result.Name)
+		assert.Equal(t, "", result.Description)
 		assert.Equal(t, primaryKey, result.AttributeKey)
 	})
 
 	t.Run("Get all fields except attribute key", func(t *testing.T) {
 		// Arrange
 		configMock := mocks.MermerdConfig{}
 		configMock.On("OmitAttributeKeys").Return(true).Once()
-		configMock.On("ShowEnumValues").Return(true).Once()
+		configMock.On("ShowDescriptions").Return([]string{"enumValues", "columnComments"}).Once()
 
 		// Act
 		result := getColumnData(&configMock, column)
 
 		// Assert
 		configMock.AssertExpectations(t)
 		assert.Equal(t, columnName, result.Name)
-		assert.Equal(t, enumValues, result.EnumValues)
+		assert.Equal(t, "<"+enumValues+"> "+comment, result.Description)
 		assert.Equal(t, none, result.AttributeKey)
 	})
 
 	t.Run("Get only minimal fields", func(t *testing.T) {
 		// Arrange
 		configMock := mocks.MermerdConfig{}
 		configMock.On("OmitAttributeKeys").Return(true).Once()
-		configMock.On("ShowEnumValues").Return(false).Once()
+		configMock.On("ShowDescriptions").Return([]string{""}).Once()
 
 		// Act
 		result := getColumnData(&configMock, column)
 
 		// Assert
 		configMock.AssertExpectations(t)
 		assert.Equal(t, columnName, result.Name)
-		assert.Equal(t, "", result.EnumValues)
+		assert.Equal(t, "", result.Description)
 		assert.Equal(t, none, result.AttributeKey)
 	})
 }

diagram/erd_template.gommd

@@ -3,7 +3,7 @@ erDiagram
 {{- range .Tables}}
     {{.Name}} {
     {{- range .Columns}}
-        {{.DataType}} {{.Name}} {{.AttributeKey}} {{- if .EnumValues}}"{{.EnumValues}}"{{end -}}
+        {{.DataType}} {{.Name}} {{.AttributeKey}} {{- if .Description}}"{{.Description}}"{{end -}}
     {{- end}}
     }
 {{end -}}

exampleRunConfig.yaml

@@ -20,6 +20,8 @@ encloseWithMermaidBackticks: false
 debug: false
 omitConstraintLabels: false
 omitAttributeKeys: false
-showEnumValues: false
+showDescriptions:
+  - enumValues
+  - columnComments
 showSchemaPrefix: true
 schemaPrefixSeparator: "_"