feat: add mssql info extraction script

scripts/mssql-info-test/main.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"database/sql"
+	"time"
+
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
+	_ "github.com/microsoft/go-mssqldb"
+	log "github.com/sirupsen/logrus"
+)
+
+func main() {
+	log.SetFormatter(&log.TextFormatter{
+		FullTimestamp:   true,
+		TimestampFormat: time.StampMilli,
+	})
+	log.SetLevel(log.DebugLevel)
+
+	db, err := sql.Open("sqlserver", config.App.SourceDbUrl)
+	if err != nil {
+		log.Fatal("Unexpected error connecting to mssql", err)
+	}
+
+	log.Debug(config.App.SourceDbUrl)
+
+	if err := db.Ping(); err != nil {
+		log.Fatal("Couldn't ping mssql db", err)
+	}
+
+	schema := "test"
+	table := "migration_test"
+
+	columns, err := getTableMetadata(db, schema, table)
+	if err != nil {
+		log.Fatal("Unexpected error extracting table info", err)
+	}
+
+	log.Info("Table info:")
+
+	for _, c := range columns {
+		log.Infof("%+v", c)
+	}
+}
+
+type ColumnInfo struct {
+	Name           string
+	UserDataType   string
+	SystemDataType string
+	MaxLength      int16
+	Precision      uint8
+	Scale          uint8
+	Nullable       bool
+	IsIdentity     bool
+}
+
+func getTableMetadata(db *sql.DB, schema, table string) ([]ColumnInfo, error) {
+	query := `
+SELECT 
+	c.name AS column_name,
+	t.name AS user_type_name,
+	bt.name AS system_type_name,
+	c.max_length,
+	c.precision,
+	c.scale,
+	c.is_nullable,
+	c.is_identity
+FROM sys.columns c
+JOIN sys.types t ON c.user_type_id = t.user_type_id
+JOIN sys.types bt ON c.system_type_id = bt.system_type_id AND bt.user_type_id = bt.system_type_id
+JOIN sys.tables st ON c.object_id = st.object_id
+JOIN sys.schemas s ON st.schema_id = s.schema_id
+WHERE s.name = @schema AND st.name = @table
+ORDER BY c.column_id;`
+
+	rows, err := db.Query(query, sql.Named("schema", schema), sql.Named("table", table))
+	if err != nil {
+		log.Warn(err)
+
+		return nil, err
+	}
+	defer rows.Close()
+
+	var columns []ColumnInfo
+	for rows.Next() {
+		var c ColumnInfo
+		err := rows.Scan(
+			&c.Name,
+			&c.UserDataType,
+			&c.SystemDataType,
+			&c.MaxLength,
+			&c.Precision,
+			&c.Scale,
+			&c.Nullable,
+			&c.IsIdentity,
+		)
+
+		if err != nil {
+			log.Warn(err)
+
+			return nil, err
+		}
+
+		columns = append(columns, c)
+	}
+
+	return columns, nil
+}