fork github.com/doug-martin

sqlgen/truncate_sql_generator.go

@@ -0,0 +1,64 @@
+package sqlgen
+
+import (
+	"strings"
+
+	"git.fsdpf.net/go/db/v2/exp"
+	"git.fsdpf.net/go/db/v2/internal/errors"
+	"git.fsdpf.net/go/db/v2/internal/sb"
+)
+
+type (
+	// An adapter interface to be used by a Dataset to generate SQL for a specific dialect.
+	// See DefaultAdapter for a concrete implementation and examples.
+	TruncateSQLGenerator interface {
+		Dialect() string
+		Generate(b sb.SQLBuilder, clauses exp.TruncateClauses)
+	}
+	// The default adapter. This class should be used when building a new adapter. When creating a new adapter you can
+	// either override methods, or more typically update default values.
+	// See (github.com/doug-martin/goqu/dialect/postgres)
+	truncateSQLGenerator struct {
+		CommonSQLGenerator
+	}
+)
+
+var errNoSourceForTruncate = errors.New("no source found when generating truncate sql")
+
+func NewTruncateSQLGenerator(dialect string, do *SQLDialectOptions) TruncateSQLGenerator {
+	return &truncateSQLGenerator{NewCommonSQLGenerator(dialect, do)}
+}
+
+func (tsg *truncateSQLGenerator) Generate(b sb.SQLBuilder, clauses exp.TruncateClauses) {
+	if !clauses.HasTable() {
+		b.SetError(errNoSourceForTruncate)
+		return
+	}
+	for _, f := range tsg.DialectOptions().TruncateSQLOrder {
+		if b.Error() != nil {
+			return
+		}
+		switch f {
+		case TruncateSQLFragment:
+			tsg.TruncateSQL(b, clauses.Table(), clauses.Options())
+		default:
+			b.SetError(ErrNotSupportedFragment("TRUNCATE", f))
+		}
+	}
+}
+
+// Generates a TRUNCATE statement
+func (tsg *truncateSQLGenerator) TruncateSQL(b sb.SQLBuilder, from exp.ColumnListExpression, opts exp.TruncateOptions) {
+	b.Write(tsg.DialectOptions().TruncateClause)
+	tsg.SourcesSQL(b, from)
+	if opts.Identity != tsg.DialectOptions().EmptyString {
+		b.WriteRunes(tsg.DialectOptions().SpaceRune).
+			WriteStrings(strings.ToUpper(opts.Identity)).
+			Write(tsg.DialectOptions().IdentityFragment)
+	}
+	if opts.Cascade {
+		b.Write(tsg.DialectOptions().CascadeFragment)
+	} else if opts.Restrict {
+		b.Write(tsg.DialectOptions().RestrictFragment)
+	}
+}