mirror of https://github.com/jackc/pgx.git
148 lines
3.9 KiB
Go
148 lines
3.9 KiB
Go
package pgxtype
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import (
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"context"
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"errors"
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"github.com/jackc/pgx/v5"
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"github.com/jackc/pgx/v5/pgconn"
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"github.com/jackc/pgx/v5/pgtype"
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)
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type Querier interface {
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Exec(ctx context.Context, sql string, arguments ...interface{}) (pgconn.CommandTag, error)
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Query(ctx context.Context, sql string, optionsAndArgs ...interface{}) (pgx.Rows, error)
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QueryRow(ctx context.Context, sql string, optionsAndArgs ...interface{}) pgx.Row
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}
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// LoadDataType uses conn to inspect the database for typeName and produces a pgtype.DataType suitable for
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// registration on ci.
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func LoadDataType(ctx context.Context, conn Querier, ci *pgtype.ConnInfo, typeName string) (pgtype.DataType, error) {
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var oid uint32
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err := conn.QueryRow(ctx, "select $1::text::regtype::oid;", typeName).Scan(&oid)
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if err != nil {
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return pgtype.DataType{}, err
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}
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var typtype string
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err = conn.QueryRow(ctx, "select typtype::text from pg_type where oid=$1", oid).Scan(&typtype)
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if err != nil {
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return pgtype.DataType{}, err
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}
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switch typtype {
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case "b": // array
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elementOID, err := GetArrayElementOID(ctx, conn, oid)
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if err != nil {
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return pgtype.DataType{}, err
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}
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var element pgtype.ValueTranscoder
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if dt, ok := ci.DataTypeForOID(elementOID); ok {
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if element, ok = dt.Value.(pgtype.ValueTranscoder); !ok {
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return pgtype.DataType{}, errors.New("array element OID not registered as ValueTranscoder")
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}
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}
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newElement := func() pgtype.ValueTranscoder {
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return pgtype.NewValue(element).(pgtype.ValueTranscoder)
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}
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at := pgtype.NewArrayType(typeName, elementOID, newElement)
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return pgtype.DataType{Value: at, Name: typeName, OID: oid}, nil
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case "c": // composite
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panic("TODO - restore composite support")
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// fields, err := GetCompositeFields(ctx, conn, oid)
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// if err != nil {
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// return pgtype.DataType{}, err
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// }
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// ct, err := pgtype.NewCompositeType(typeName, fields, ci)
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// if err != nil {
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// return pgtype.DataType{}, err
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// }
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// return pgtype.DataType{Value: ct, Name: typeName, OID: oid}, nil
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case "e": // enum
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members, err := GetEnumMembers(ctx, conn, oid)
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if err != nil {
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return pgtype.DataType{}, err
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}
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return pgtype.DataType{Value: pgtype.NewEnumType(typeName, members), Name: typeName, OID: oid}, nil
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default:
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return pgtype.DataType{}, errors.New("unknown typtype")
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}
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}
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func GetArrayElementOID(ctx context.Context, conn Querier, oid uint32) (uint32, error) {
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var typelem uint32
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err := conn.QueryRow(ctx, "select typelem from pg_type where oid=$1", oid).Scan(&typelem)
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if err != nil {
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return 0, err
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}
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return typelem, nil
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}
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// TODO - restore composite support
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// GetCompositeFields gets the fields of a composite type.
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// func GetCompositeFields(ctx context.Context, conn Querier, oid uint32) ([]pgtype.CompositeTypeField, error) {
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// var typrelid uint32
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// err := conn.QueryRow(ctx, "select typrelid from pg_type where oid=$1", oid).Scan(&typrelid)
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// if err != nil {
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// return nil, err
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// }
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// var fields []pgtype.CompositeTypeField
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// rows, err := conn.Query(ctx, `select attname, atttypid
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// from pg_attribute
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// where attrelid=$1
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// order by attnum`, typrelid)
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// if err != nil {
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// return nil, err
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// }
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// for rows.Next() {
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// var f pgtype.CompositeTypeField
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// err := rows.Scan(&f.Name, &f.OID)
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// if err != nil {
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// return nil, err
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// }
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// fields = append(fields, f)
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// }
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// if rows.Err() != nil {
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// return nil, rows.Err()
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// }
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// return fields, nil
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// }
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// GetEnumMembers gets the possible values of the enum by oid.
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func GetEnumMembers(ctx context.Context, conn Querier, oid uint32) ([]string, error) {
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members := []string{}
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rows, err := conn.Query(ctx, "select enumlabel from pg_enum where enumtypid=$1 order by enumsortorder", oid)
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if err != nil {
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return nil, err
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}
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for rows.Next() {
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var m string
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err := rows.Scan(&m)
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if err != nil {
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return nil, err
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}
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members = append(members, m)
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}
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if rows.Err() != nil {
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return nil, rows.Err()
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}
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return members, nil
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}
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