Data model generator for postgres database.

generator/metadata/column_info.go

@@ -0,0 +1,116 @@
+package metadata
+
+import (
+	"database/sql"
+	"github.com/serenize/snaker"
+)
+
+type ColumnInfo struct {
+	Name       string
+	IsNullable bool
+	DataType   string
+	TableInfo  *TableInfo
+}
+
+func (c ColumnInfo) IsUnique() bool {
+	for _, uniqueColumn := range c.TableInfo.PrimaryKeys {
+		if uniqueColumn == c.Name {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (c ColumnInfo) ToGoVarName() string {
+	return snaker.SnakeToCamelLower(c.TableInfo.Name) + snaker.SnakeToCamel(c.Name) + "Column"
+}
+
+func (c ColumnInfo) ToGoType() string {
+	typeStr := c.GoBaseType()
+	if c.IsNullable {
+		return "*" + typeStr
+	}
+
+	return typeStr
+}
+
+func (c ColumnInfo) GoBaseType() string {
+	if forignKeyTable, ok := c.TableInfo.ForeignTableMap[c.Name]; ok {
+		return snaker.SnakeToCamel(forignKeyTable)
+	} else {
+		switch c.DataType {
+		case "boolean":
+			return "bool"
+		case "smallint":
+			return "int16"
+		case "integer":
+			return "int"
+		case "bigint":
+			return "int64"
+		//case "date" : return "time.Time"
+		case "bytea":
+			return "[]byte"
+		case "text":
+			return "string"
+		default:
+			return "string"
+		}
+	}
+}
+
+func (c ColumnInfo) ToGoDMFieldName() string {
+	if forignKeyTable, ok := c.TableInfo.ForeignTableMap[c.Name]; ok {
+		return snaker.SnakeToCamel(forignKeyTable)
+	} else {
+		return snaker.SnakeToCamel(c.Name)
+	}
+}
+
+func (c ColumnInfo) ToGoFieldName() string {
+	return snaker.SnakeToCamel(c.Name)
+}
+
+func fetchColumnInfos(db *sql.DB, tableInfo *TableInfo) ([]ColumnInfo, error) {
+
+	query := `
+SELECT column_name, is_nullable, data_type 
+FROM information_schema.columns
+where table_schema = $1 and table_name = $2
+order by ordinal_position;`
+
+	//fmt.Println(query)
+
+	rows, err := db.Query(query, tableInfo.DatabaseInfo.SchemaName, &tableInfo.Name)
+
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	ret := []ColumnInfo{}
+
+	for rows.Next() {
+		columnInfo := ColumnInfo{}
+		var isNullable string
+		err := rows.Scan(&columnInfo.Name, &isNullable, &columnInfo.DataType)
+
+		columnInfo.IsNullable = isNullable == "YES"
+
+		if err != nil {
+			return nil, err
+		}
+
+		columnInfo.TableInfo = tableInfo
+
+		ret = append(ret, columnInfo)
+	}
+
+	err = rows.Err()
+
+	if err != nil {
+		return nil, err
+	}
+
+	return ret, nil
+}